A8N VM has 6100 onboard graphics. U can add some 256 MB of video mem as shared. U can at least play newer games but at lowest possible settings for most games. Adding more mem nd increasing shared mem on this mobo make some gr8 differences.
What I suggest isu should only buy 512 mb mem now nd buy a 7300GS or even GT for 3.5k or 5.5k. It makes more difference in adding any of these cards than adding another 512mb.
Lastly, get the ASUS A8NE mobo instead of A8NVM. A8NE has nforce 4 ultra chipset nd is gr8 on overclocking. U can easily run a 3800+ at 2.4 or 2.6 or even higher with good stability on this board nd the onboard sound[realtec 7.1] is much better than the VMs[soundmax]. All in all its a good future proof board which help to get every ounce of perfomance from every hardware on ur PC.