Hubble is low enough for comms to be pretty quick. A quick ATV trip could have load of fuel up there to keep hubble in the sky, as well as a permenant robonaut for sensible repairs.

Heck - having a couple up there all the time could be a good way of fixing anything - given time chaning orbits is the cost, not waiting to catch the errant sattelite, and IIRC the ATV had a pretty good load capacity to LEO