You want to be looking at a core 2 duo processor mate, fast/cheap which is right up your street isnt it

processor http://www.ebuyer.com/UK/product/126906
motherboard http://www.ebuyer.com/customer/produ...uct_uid=124405
Memory http://www.ebuyer.com/customer/produ...duct_uid=92879
graphics card http://www.ebuyer.com/UK/product/119712/rb/0

All picked with your description of needs in mind