AMD only made 2 Phenom II X4 CPU's for AM2+, 920 and 940, both were 125watt which exceeds the boards capability. I as well suggest upgrading the whole thing.
Agreed. I had the Narra6 board and ran a 955 on it, it only took a few months for the VRM to blow completely. You can pick up a baseline AM3+ Motherboard and an FX4300 for sub $200.