GT220?!!!
Not a very good gaming GPU.
If you cant be arsed to build one yourself (which is always the better option) try:
http://www.desktop-option.co.uk/index.php?cPath=13_18
I got mine from there 2 years ago - good value for money. Pay by Direct Debit or Paypal though (heh - I payed by transfer and it delayed shipping by 2 weeks)
Or just get one from
http://cclonline.com
Buy it in bits and build it yourself.
A Radeon 5770 is a Directx11 card with reasonable performace and a �110 price tag.
CCL have some ready built PCs aswell, I would recommend them, have bought many things from them in the past and the service and prices are good.
Problem with Dells and HPs, Compaqs etc is that most of the hardware is OEM - your GPU might not support new drivers as they come out, unlike if you buy retail versions.