that would depend on the shop, how good they are and how fast they can get the parts they need. With a tranny rebuild, you'll need new seals, bearings, synchro blocking rings at the least. and depending on how long and how bad the synchros were grinding, you might also need new speed gears. the list can grow depending on how much a shop would wanna rape you. Try replacing the fluid first. It would be a very cheap alternative and it might buy you just enough time til your ready for your swap. try GM(yes general motors) synchromesh, part #12345349, they are a very good band aid on worn synchros.
good source for used parts:
www.xcars.com