My Dad added some brake fluid to the auto transmission on my old Chevy Impala, this was at around 135,000 miles, we changed the fluid soon afterwards, I am now over 200,000 and the transmission is still working fine.
Now on the power steering, I would suggest trying one of the Dexron-based stop leak formulas, I have no specific experience so don't know which one is better or worse. Go with a brand you recognize.
A rebuilt rack is not *that* expensive or hard to install.
If your steering rack boots have been torn for some time (I guess they must be leaking or you wouldn't see the leaking PS fluid) probably the seals on each end of the rack are shot. Again it's not that hard to change the rack. You don't have to separate the tie rod ends, just unscrew them as if you were setting the toe-in. Work carefully and know what you are doing when working with steering, or find a shop that knows.
Avoid cranking the steering back and forth without moving the car, particularly when it's cold out. I know if you park on the street in in a Northern city this advice is not too practical, but even in that case try to move the car either forward or backward while you are turning the steering wheel.