Just 512MB or 2x512MB??
better the latter!!
for 18k, i think you can get any of the following, with no onboard gfx options but definitely improved gaming experience-
Transcend512MB + A8NE 2.0 + XFX6600(nonGT) + 939pin 3000+
2k + 5.5k + 5.5k + 5.5k!!
2x512MB + foxconnNF4XK8MC/Asrock Dual SATA + XFX6600 + 939 3000+
4k + 3k/3.5k + 5.5k + 5.5k!!
(add A8NE here instead of other two if more features and better quality reqd and budget bit more flexible)
prices approx '+/- 100to200 bucks per item'.
Please confirm all rates, especially XFX6600!!
For mobo with onboard gfx,
value version of A8N- VM CSM is the A8N-VM costing 4k!!