You will probably get a better boost in FPS with a graphics card upgrade than a CPU upgrade. Because its the BE, I would over clock it as much as possible so you can upgrade the GPU and get much better performance. http://www.cpubenchmark.net/cpu_lookup.php?cpu=AMD+Phenom+II+X4+965
I would note, it's important to remember that most games are more graphics card dependent. So could you please post what games you are interested in?