You can get them at any auto parts store...
They are universal...They usually come in tubular or stacked plate designs. I used a stacked plate Hayden cooler on my probe atx back in the day.
Install is rather easy, as you need to run the line that goes out from the stock cooler (which is part of the stock radiator), and into the "IN" of the new cooler, and then the "out" of the new cooler returns to the tranny. The cooler gets mounter infront of the radiator...
I don't know what fittings, or what sized hose you need, so if someone who's installed one on a coug could post here to help you with that, then you'll be all set.