Tranny options? Options

[Nano]

Well, long story short, Ive got a problem with my current transmission that can't realistically be fixed without changing it into a new housing, or just getting a new transmission.

What are my options on transmissions? what transmissions are roughly compatible with a more or less stock 99 celica, and what can get me the best bang for the buck, performance wise, in an auto ( if thats even possible ).

If not, what cars have the same tranny's, so i could just get a pull from a car here?

For reference my toyota dealer wants 900 for a used tranny, and 700 to install it, and im aiming to spend quite a bit less than that, if at all possible.