You could spend 40 quid on another 2x1GB for your existing board giving you 3GB or a lot less on another pair of 512's giving you 2GB, yes it's money on a DDR but it's going to be a comparatively cheap upgrade compared to buying a new board, ram and cpu/heat sink and possibly PSU. A well known auction site is probably your best bet as OCUK is out of stock on DDR.