2007-2009
If the HST can hold out long enough, and NASA can actually get out of its own way, one could launch a CEV with astronauts ready for a spacewalk, and if the instruments are too big for the CEV, launch them separately in an unmanned fairing with automatic rendezvous. The latter could be launched months earlier, and hang around a few miles from the Hubble until needed. The real trick would be stabilizing the scope without the Shuttle and its robot arm, but I bet it could be done.
I get a bit tired of NASA's odd habit of trying to scratch dirt over old projects as soon as humanly possible, almost like they're ashamed of them.