WildCard999 :
Intel Core 2 Quad socket lga775 for $54 on Amazon
http://pcpartpicker.com/part/intel-cpu-hh80562ph0568m
That's a good suggestion IF, and ONLY IF the motherboard can handle that 105W CPU.
OP -> You need to check the "AA revision" of you motherboard. There were a whole range of boards produced under the "dq965gf" model number, they have differing quality of power delivery which determines the CPUs they can safely run. That's specified by the "AA revision" of the motherboard. It should be printed near the model number on the motherboard. Or you might be able to get it from the BIOS.
Once you have that AA revision, check the Intel CPU compability list here:
http://processormatch.intel.com/Processors/CompatibleProcessors?componentName=dq965gf
to confirm that the CPU recommended by @WildCard999 lists your AA revision in it's supported list.
There is, for example, a D41676-305 revision of your dq965gf which will handle a Core2Duo, but not a Core2Quad.
Find the best processor you can for your motherboard revision.
Those Core2Duo/Quad processors aren't too bad. With something like a 750ti, you'd be able to have a decent entry level gaming experience.