Best guess. Should be hundreds (~$850) if its just the clutch/pp. (By comparison, recent Mustang fix was $375).
Good four figures ($2k) for synchros and gears. (Working off of a lost 1st gear on my X 1/9).
Whole trans, find a donor or a rebuilt (not likely) if you have time and inclination. ($2k+ parts).
If you need a trans and have it replaced, you're looking at $5500+ w/labor. >$6k at dealer.
2 days to a week down.
Sry for the bad news.