My understanding of the HST situation is that it isn't a matter of money.
There is simply no way to fix it right now. The shuttle is grounded and until that breaks loose, there is no mechanism short of a new manned space program to get an astronaut up there to replace the gyros and other mechanisms that need replacing.
TM
The argument by some (not me BTW), is that even after NASA starts flying again, a mission to Hubble will be too dangerous.
(No space station to use as a "life boat" if a Shuttle is damaged on ascent)