With that budget and gaming in mind, wouldn't it be better to treat yourself to a new graphics card too?
Asus GeForce GTX 470 V2 1280MB GDDR5 PCI-Express Graphics Card with MAFIA 2 £224.99
(£191.48) £224.99
(£191.48)
AMD Phenom II X4 Quad Core 955 Black Edition "125W Edition" 3.20GHz (Socket AM3) - Retail £111.61
(£94.99) £111.61
(£94.99)
Asus M4A87TD/USB3 AMD 870 (Socket AM3) DDR3 Motherboard £86.99
(£74.03) £86.99
(£74.03)
OCZ Reaper Low-Latency 4GB (2x2GB) DDR3 12800C6 (1600MHz) Dual-Channel (OCZ3RPR1600C6LV4GK) £86.94
(£73.99) £86.94
(£73.99)
Sub Total : £434.49
Shipping cost assumes delivery to UK Mainland with:
DPD Next Day Parcel
(This can be changed during checkout) Shipping : £9.50
VAT is being charged at 17.50% VAT : £77.70
Total : £521.69
Also welcome to the forum and congrats on getting into uni!
edit: Guess you'll also be needing a cooler if you want to overclock, if you want to keep it closer to the £500 budget with a cooler included you could switch the graphics card to this one:
http://www.overclockers.co.uk/showproduct.php?prodid=GX-064-GI&groupid=701&catid=56&subcat=1830
and it would still be a decent upgrade.
This would be a decent cooler:
http://www.overclockers.co.uk/showproduct.php?prodid=HS-072-AK