Dave the card Loz found for £66 or £32 pounds is more than enough for the game you want to play. It has the M10 chip and that has been an industry standard chip for a while. If you want to go up from there look more at memory rather than M11 chip etc.
So 256mb is better than 128mb... If you can find a card using DDR 3 mem then even better. Fro £150 you wot get better than this in my opinion....
http://www.ebuyer.com/customer/produ...duct_uid=86362
This card will be good for a long time....
Here is all the jargon on this card
http://www.connect3d.com/products/agp_x800.htm get this and your games will fly faster than your pixel planes lol