Graphics Card and RAM Advice

I want to get a new graphics card that is not too expensive and that it could run most of the new games for PC. Also, I have found 1GB of RAM on the circuit city website, heres the link: http://www.circuitcity.com/ccd/productDetail.do?&oid=181158.

Should I buy the 1GB, or are there better ones for a cheaper price?

My Specs are:

Processor: Intel(R) Pentium(R) 4 CPU 2.80GHz (2 CPUs)

Memory: 502MB RAM

Chip Type: Intel(R) 82915G/GV/910GL Express Chipset