1991 Audi 100 PS fluid

[VNorman@zoomit.sikorsky.com]

Can anyone tell me the correct power steering fluid to use in a 1991 Audi 
100?
My friendly neighborhood auto store sold me a can of Pentosin CHF 11S which
they swore was the correct stuff and since I was stuck I used it. Since 
then I have
been told that the correct fluid is red (the CHF 11S is green). The color 
of the 		
original fluid in the car was difficult to figure out, but it didn't look 
red....
Have I just destroyed my steering rack and brake pressure accumulator? Is 
it
possible to completely drain the current fluid out?
On a somewhat related topic, where can I buy a brake pressure accumulator 
for
a reasonable price? Come to that, why are they so expensive- the bomb in my
BMW 635 can be bought for about $55. Do these things routinely fail after 
about
100,000 miles?