TD you best bet is to call around to some trans shops and ask for a quote. let them know whats wrong, with that many miles your better off with a full rebuild though. a reputable show will like charge 1200-2000. i had a stock rebuild a few years ago when i lost forth gear and it was 1500.

hard shift, make sure you have enough fluid, you could be low. get the trans to opperating temp after driving around so the trans has gone through all gears and then check the dipstick with the car running. if there was alot of sludge/clutch material when you did the fluid filter change then you might need new clutches.