That's because the Phenom 9600 is a super, super slow CPU for modern gaming and you are CPU bottlenecked.
You need to upgrade your CPU... I don't know off hand if that motherboard supports socket AM2+/AM3 CPUs but you could upgrade to a Phenom II x4 or x6.
It says AM2+ when i look it up online so im not possitive. What would you suggest to upgrade to at a low end price that will support the speed of the Radeon HD 7770?