Further, just PUT KIRK ON ANOTHER SHIP. Your plot has to make sense, or it won't be believable, and will suffer.
Gah, this movie sucks.
It's not like they didn't just do a pass of the Excelsior in spacedock on that very first scene. Or are they saying that it's still broken from whatever Scotty did to it in ST3? Wait.. I bet there's someone who could fix that pretty easily anyways!