New graphics card?

I forgot to mention that my mother is the Sabertooth 990fx, if it matters.

You mean your motherboard presumably? :-) Well the 7770 has the most raw power of those cards, though I'd take the GTX650. It has adaptive v-sync, so that if you're using v-sync to prevent tearing and your framerate drops below 60, the GTX650 won't restrict your framerates like the Radeons will. Basically it switches v-sync on only when needed to achieve its purpose, then gives you superior performance the rest of the time.