i considered this myself many a time but have decided to sell and buy something faster with a 5 speed.
you would need the tranny clutch pressure plate maybe new flywheel throw out bearing pedal master and slave cylinders some hydraulic lines i think and some other little things.
i think i was looking between $1500 to $2000 for a swap but i hear they can get up to $4000 and beyond just ot buy the tranny new i think.
all in all its not worth it unless ur going to swap the engine out too and rebuild or whatever. if its a turbo mk3 supra i can maybe seeing it on something like that. but then again you shouldve just bought a 5speed before you got sunk into ur current car just like i did.