Check the phone book or look online. There's bound to be some upholstery repair places around you. If you know anyone that works for a dealership ask them who they use to repair leather seats. There are usually vendors that go to dealerships and perform repairs on sight. But you have to be careful about the quality of the repair.
+1 on the upholstery shop. They will give the best options and prices. Some dealerships will just try to sell you the whole seat outright. you might even get lucky. My inlaws for instance have a re-upholstery shop and just charge for labor because the material is leftover from a couch or something, so the material was already paid for. Just depends on the shop.
91 Red GT (sold)
03 Sonic Blue Mach1 (stock) (in mustang heaven :()
07 Vista Blue GT; KenneBell Blown
Go to newtakeoff.com they sell oem leather and other oem stuff cheap. It all comes from roush, saleen, and Shelby. They take of the oem stuff and put there own products on ie wheels, bumpers, etc. They can't sell it as new because there a few miles on them.