Get faction up - Cenarion Expedition have some nice recipes for a bit later on. Check Shattrath, as previously stated, and check your speciality trainer (tribal, etc.) as they have new recipes too. They don't kick in until a bit later either, but remember to check it out!
I would also check back with the GM leatherworker trainer, as according to the list here, you should have 3 patterns rated at 320. Push on to 325 and then make Heavy knothide leather once you get the pattern, as you'll be needing tons of it for later!
Hope this helps