I'd say upgrade your memory at the same time as your graphics card...

CPU is a bit on the slow side for the newest of games, but it will run them OK with a decent graphics card and a handful of memory.

224Mb would "probably" be a 128Mb, a 64Mb and a 32Mb SDRAM chip, unless it's Windoze reading the amount wrong......whichever way, I'd say to upgrade it to at least 512Mb (1024Mb if you can afford to), but you'd need to check if your motherboard can support 1024Mb if you were going to get that much.