Just did some digging.

Your 2G has a 23 Spline Tranny Output Shaft. I found that info here;
http://members.shaw.ca/costall/1000Q/

Here is some information relating to Gear ratio;
http://www.vfaq.com/mods/Trannies.html

It is hard to say without seeing the guts but the odds are that their is lots of damage inside your Tranny so it might be way to much $$$ to rebuild your Tranny.

Your best bet would be to get another Tranny from someone that is parting a 2G. Look in the for sale or put a post in the wanted, it might be hard but you never know.

You could also get one from Thomas Toth. Ryan W bought one from him.

One last posibility would be to get a 1G Tranny and put the guts inside your Case. 1G and 2g Tranny are very similar.

Whatever you do make sure that you are buying a good working Tranny, otherwise you'll be redoing it over again in no time.

Ghislain.