Upgrading my PC

[deceebs]

Hey all, im new here and in need of some advice.

I want to upgrade my PC, and was wondering whats the best upgrade for this for up too about $600 AUD

Incase you wanted to know what i have look below,

My Current PC Stats:
CPU: Intel Quad Core Q8400 2.66ghz
RAM: 4GB DDR2 or 3 im not too sure
GC: Nvidia GeForce Gt 220
MB: Gigabyte S-Series G41MT-ES2L
Memory: 800gb HDD + 500gb external

But yeah this comp needs some speeding up
Any help is greatly appreciated and if you've got any questions as to what other junk is in the box or whatever just ask (;

Thanks

 

[Yami]

What are you using this system for? Gaming, or just office/internet stuff?

 

[deceebs]

I do alot of gaming im a 17yo male with a alot of time to spare >_> so something that could run new games on decent/good settings would be awesome