Will my pc do the job?

[OhMargott]

Hey, I would like to know if changing my processor could help with fps
My pc:
-Graphic card: GeForce GT240
-Processor: Intel Celeron 430 1.80 GHZ
-4 GB RAM
-Win 7 x64

My question is: I know my processor sucks, but just to make sure, replacing it for an i5 or i7 would help? Is my graphics card also a problem or it's not affecting my fps? Right now I'm running the game maxed out and I get 11-12 fps. I noticed that when I turn antialiasing and FXAA on I get a fps drop. Is that a bad signal from the graphics card?