Yep, you need a pci-express card.
Geforce ( nVidia ) - 7600 - PCI-Express, click here
If you can stretch your budget to £143.00 Inc VAT this card is excellent value and is great for games (a friend has one), Sapphire Radeon X1900 GT PCI-E , at click here.
All links go to Scan (I use them a lot) pages.
Hope this helps.