undervolt it and hope that it doesnt burn out the power regulators on the motherboard, thats my only suggestion. Generally the wattage rating is because of the power regulation circuit or the cooling that it has, and if the VRMs go the board is dead.
You are going to have problems with this system! It will work fine until you try to play a new game and then crash-o-rama. What hunter315 says about burning out the motherboard is true. Either, get a new motherboard or a 95w AMD PHENOM II X4 945.
The 965 is not on the supported CPU list on the ASUS website for this motherboard, my guess is that its working because the processor is stepping down and running at a lower speed than its capable of. M4A78LT-M does support this chip, maybe the LE version is a light edition? Not sure but is looks at first glance your out of luck, maybe ASUS will come out with a BIOS update in the future to add support, I'd check their site often for updates.