Hi Hans, Welcome to the club!
Like Mark said, check with the dealer or go to Car-part.com and see what your options are for replacement transmisssions. In the trunk of your car on top of the spare tire cover you should find a "build sheet" with your VIN (should match the one under your windshield and the partial one on your transaxle). This sheet will also be covered with three character codes referred to as RPO (regular production options). There you will find the gear ratio code for your transaxle. It should begin with an F or G. Go to techinfo here and choose specifications / rpo codes for a list of definitions.
The trans itself should also have a riveted metal tag on the rear passenger side with information describing the year, model and type of trans. The model is repeated in two large characters on the ID tag. The safest course is to use the same year, model and type of replacement trans. No troubles with compatibility then.
[edit: if you are not supercharged, car-part search indicates you have either an F17 (2.84) or FW2 (3.06) gear ratio, and that your trans option was used in 96 Pontiac, Buick, Olds and 97 Buick, if I did it right. Do check Car-part yourself and confirm the info w the dealer. Before you pay for a replacement trans, make sure the model and type match on the ID tags. Salvage yards have been known to try to sell trannies that don't match.]