I replace the PS rack in my B5 A4, it was a piece of cake compared to some “rountine” jobs like the TB or all 8 CAs.
http://www.scaudi.com/howto/steeringrack/rackwriteup.html
The rack is very expensive though. The leak is more likely one of the high pressure lines, but could easily just be a crack in a hose going to the cooler, impossible to tell w/out looking. If it was the rack, it would drain the fluid in about 24 hours, not a slow leak.
AWD > FWD, and it still sounds like you can’t afford the car, why not buy something else? The 96s were crapola.