Are you sure that it is your gearbox? May be clutch or cable related. What is happening to make you think it is stuffed?

Getting gearboxes fixed usually is pretty dear depending on the problem, for my stumpy 5 speed I got quoted ($600 for new bearings and syncro's)
4 speed boxes are very common, I'm sure there are alot of 4 speeds still lying around in peoples garages, ask around for one as you can get them for $50.

I hope I've helped
Cheers
Damo

i know theres someone out there that wil say what a dumbass, but i have to ask, i dont know much about these sorts of things...my gearbox is starting to stuf up and i was wondering where i can get it fixed or if worst comes to worst, do i have to buy i new one. (i have a standard 4spd 1200 ute gearbox). Id rather a 5spd but theyre very expensive and hard to get hold of.