As a Dwarf, I am proud to report that 25-man Kel'thuzad drops a gun. Unfortunately, until you can get there, it's more crossbows for everyone. The Drake-Mounted Crossbow from Heroic Utgarde Keep will likely be your best option at the 5-man level for ranged DPS.
The heroic dungeons are apparently the time for dual wielding hunters to shine. All of the two-handed weapons seem to focus mostly on strength, making them ill suited to be a Hunter's stat stick. However, multiple one-handed weapons with plenty of hit rating, attack power, and agility drop. Your best bet for heroic weapons will probably be The Fleshshaper from heroic Halls of Stone, and the Dagger of Betrayal from heroic Utgarde Keep. Both have the best balance of DPS stats, and will go a long way to helping you hit the hit rating cap as well. If you're in heroic Violet Hold, keep an eye out for The Key from Lavanthor as well.
As far as trinkets go, The Mirror of Truth is definitely a candidate for the first item you should spend your Emblems of Heroism on. Not only does it have a lot of critical strike rating, but that attack power proc is far from anything to sneeze at.
For your other trinket slot, get the Sphere of Red Dragon's Blood from Keristraza. The hit rating it has will free you up to equip other stats elsewhere. If you're find on hit rating, though, I might stick with the Oracle Talisman of Ablution, but you can also try picking up the Incisor Fragment from King Dred in heroic Drak'tharon Keep.
For Rings, you're definitely going to want to consider going after the Mobius band from the Heroic version of the Culling of Stratholme. The hit rating you need is combined with large amounts of the agility and attack power you love. Other than that, you'll probably want to stick to the Ring of Scarlet Shadows that we discussed last week. The Prospector's Prize from heroic Halls of Stone might work in a pinch if you're really desperate for hit rating, but with no agility or attack power, and lots of haste, many Hunters may find it lacking quite a bit.
For your neck, you'll probably want to save up some Emblems of Heroism and purchase the Pendant of the Outcast Hero in Dalaran. In the meantime, the Necklace of Arcane Spheres may be yours if you get Xevozz in heroic Violet Hold.
As long as you're in heroic Violet Hold, you might want to hope Erekem escapes his cell and drops the Cloak of the Gushing Wound. It's a very nice upgrade to the Cloak of Holy Extermination, especially if you need the hit rating.
In Heroic Utgarde Keep, you'll find the Plunderer's Helmet, which in addition to having a nice outlay of DPS stats, has red and meta gem sockets for further customization. This is definitely the helm to shoot for if you don't need extra hit rating beyond whatever you gem it with.
If you're in dire new of hit rating, you can take out King Dred in heroic Drak'tharon Keep for King Dred's Helm, which lacks gem slots but does have 52 hit rating and respectable DPS stats otherwise.
If you have 80 Emblems of Heroism, you can buy the Chestguard of the Lost Protector (the other way to get it is to kill Gluth in Naxxramas), which can then be turned in for the Heroes' Cryptstalker Tunic, easily the best chest you'll get out of a 5-man, and a much-needed source of hit rating in a high level chestpiece.
While you're saving up those badges, though, you may wish to consider the Hauberk of the Arcane Wraith from heroic Nexus, which comes complete with a gem slot and a nice outlay of Hunter DPS slots, lacking only hit rating. Another option is the Aviary Guardsman's Tunic, which is a zone drop in heroic Drak'tharon. Beastmasters be warned, it does have Haste.
Once you have that Cryptstalker tunic, why not get some Heroes' Cryptstalker Gloves to go with it and get that set bonus? You can attain them with 60 Emblems of Heroism by buying and turning in the Gloves of the Lost Protector.
In the meantime, killing Cyanigosa in heroic Violet Hold can net you the Handgrips of the Savage Emissary, which have competitive stats with the cryptstalker, although no gem slot or set bonus. If you need hit rating, you might also consider trying for the Grips of the Beast God off of Gal'darah in Heroic Gundrak. As a bonus, they have a nice red gem slot, perfect for more hit rating.
Keristraza in heroic Nexus will drop a very nice set of bracers in the Interwoven Scale Bracers which are very much a nice straightforward upgrade. If you need a bit of hit rating or are having bad luck with Keristraza's drops, you can grab the Raging Construct Bands from heroic Halls of Stone.
Defeating Gortok Palehoof in heroic Utgarde Pinnacle gives you a chance at the Massive Spaulders of the Jormungar, which provide a very nice 33 hit rating on top of other DPS stats which easily outpace most other comers for their level.
If you're fine on hit rating and like a little customization on your gear, you may also want to track down the Spaulders of the Abomination, which are slightly behind the massive spaulders in agility, attack power, and intellect, but do have a red gem to play around with and critical strike rating to replace the hit rating. They drop off Meathook in the heroic Culling of Stratholme.
The waist slot gives you another opportunity to spend your emblems with Vereesa's Silver Chain Belt, a solid, well-rounded DPS belt with hit rating and a blue gem socket. It goes for 40 emblems.
However, you'll want to strongly consider spending your emblems elsewhere and just picking up the Sovereign's Belt from King Ymiron in heroic Utgarde Pinnacle. It loses the armor penetration and the socket from Vereesa's belt, but has more hit rating and attack power and nearly as much agility and intellect.
Your best bet for Heroic leggings are definitely going to be the Leggings of the Stone Halls from, where else, heroic Halls of Stone. They have everything a growing Hunters needs short of hit rating.
A nice stopgap measure until you grab those is the Hollowed Mandible Legplates from Hadronox in heroic Azjol-Nerub. Though they do lag behind the Leggings of the Stone Hall in most DPS areas, they do have 2 red gem slots.
Your best bet for heroic feet will be from Keristraza in the heroic Nexus, specifically the Dragon Slayer's boots. While the haste might make Beastmasters shirk, they're far and away the best mail Hunter boots from a heroic drop, especially once you take advantage of the two red gem slots. Lavanthor in heroic Violet Hold drops the Twin Headed Boots, which are similar in stats to the dragon slayers, but lack the gem slots and replace the haste with critical strike rating.