I don't know about Horde, but here's directions for Alliance.
The next two bandage recipes (Heavy Silk and mageweave if I remember correctly) are sold in Stromgarde (Arathi Highlands) by the same npc that sells the training book for 150-225. From the entrance, hug the right wall (to avoid attracting attention from the level 35ish elites if possible), turn right at the first chance. Hug the right wall some more and, again, take a right as soon as possible. At this point you should be in an Alliance friendly area. Take another right and you will eventually come to a walkway that crosses over the path you came in on. After this the npc will be just a little to the right when you exit the walkway. Hope that makes sense.
Or you can buy them at the AH for a higher (often insane) price.