You will probably spend nearly as much for that sort of work as you would for a basic new top, and a used top can actually be cheaper if you can do the work yourself.
Sewing it on the car is a really difficult, awkward task, and then you have to waterproof the stitching. I did a little stitching repair on a jeep softop, which could be easily detatched, and it was much harder than it looked. Put it this way: I'd charge well over $200 to do a high-quality stitching job on a miata window (@$50/hr), and that is assuming the top material is not going to tear/stretch under load, which old tops are wont to do. Then there is waterproofing...
Either go full-ghetto and just Gorilla Glue the thing in place, or replace the top, IMHO.