Upgrade computer build

[Bright_Midnight]

I am looking to get more performance out of my pc and would like to know what I should to to increase my computers overall gaming performance for the cheapest amount I can. Using the build in which I will describe bellow I get about 25 fps on Ultra World of Warcraft and 50 fps with max setting super modded Minecraft but sometimes drops to 5 for no reason then jumps back up.
I also am looking to play other games like Gta Skyrim L4D2
I have a gtx 470 graphics
a good powersupply but im not sure on the watts
250 gb hard drive but Im going to add on a couple others I have
lots of fans
8 gigabytes of ram but because of the pereson who gave me the hardrive with windows 7 32 bit cant use all so its only about 3 gigabytes but I am going to upgrade to windows 8 in the future.
Decent Motherboard
And decent cpu.

 

[Alpha3031]

Can you tell me the actual CPU, instead of telling me it's decent?


EDIT: CPUZ is a good tool, if you don't know

 

[Samsamproducts]

What is the cpu, and can you check the psu wattage?

 

[popatim]

Keep in mind that you cant 'Upgrade' to 64bit from 32 bit. Its a full reinstall you're looking at doing when you go to win8.