My team went through this exactly in 2006. 30 lbs overweight with only 2 days to fix it! I would suggest removing a couple of CIMs, maybe replace some of those wheels with lighter wheels. We originally had 4 powered wheels but then we decided to have it go to 2 with a pair of omni wheels in the back. We replaced several of our thick plates with thinner ones and cheese holed the heck out of everything. Replaced all of our lexan with some thin fiberglass stuff that was nasty to work with but a lot lighter. Try to think about what kind of functionality you wouldn't mind losing. A turret is good but not necessary for this year's game. If you took that off and then had a stationary shooter it looks like your robot will still work quite nicely. Also if you have any pvc rollers, go ahead and switch them to ABS. ABS is quite a lot lighter than pvc and strong enough for most FIRST applications.
Pictures of our rookie robot, after weight savings:
http://www.chiefdelphi.com/media/photos/23240