$50 million would be more than enough to come up with something that could grab the Hubble and haul it into a higher parking orbit, although the launch costs might double that. Haven't done detailed numbers. Once that's done, you have lots of time to figure out repairs. Of course, once you have the infrastructure in place to go up and fix the Hubble properly, you also have the infrastructure to launch and service cheaper and just as effective telescopes. Might turn out that the Hubble will see its final days as an orbiting museum piece until someday the private sector has the capacity to finally bring it home to the Smithsonian.