Upgrade recommendation

[aclipse]

Here's my current specs

CPU : intel i5 750
Mainboard : Gigabyte P55A - UD3R
RAM : 4GB Kingston HyperX 1600 CL8
GPU : Gigabyte ATI Radeon 5850
http://www.gigabyte.com/products/product-page.aspx?pid=3354#ov

PSU : Corsair HX 750
Case : Coolermaster HAF 922

Monitor : Samsung SyncMaster 2233sw 22 inch
HDD 500 GB, I don't think I need more space as of now

So I'm thinking to maybe get a bit of an upgrade.
What I'm asking you guys is what parts need replacement to give the best boost to performace for the money?

The computer is mainly used for gaming and other media (movies) and office

Thanks..

If it helps, I live in Sydney Australia...

 

[intel1502]

If it was a brand new PC, i'd suggest a 2500k on the P67 platform, but as this is merely an upgrade, you'll have to compromise.
Inexpensive methods to make this build better:
1/ 8GB RAM (corsair vengeance, etc.)
2/ OCZ Agility 3 / OCZ Vertex 2 60-120GB SSD (for boot/office/games)
3/ If you're running the stock heatsink, Noctua DH-14 / XSPC Rasa 750 RS240 to allow 4GHz + O/C whilst also achieving lower temps
4/ Asus/Gigabyte/eVGA GTX570

Shop @ uMart.com.au & Gammods.com.au...
Best of luck for upcoming upgrades.

 

[aclipse]

is getting a GTX 570 much of an improvement over the 5850?

I don't OC my build, I'm still new so I don't want to try it and fail...