Hey guys I'm using 

Dell Vostro 200 Desktop Computer Intel Pentium Dual-Core Processor E2160 (1.80GHz, 1MB L2 Cache, 160GB HDD, 2GB RAM

and I want to upgrade my grahpics card but I'm not sure what watts I have, how can I increase my rams? Please give me some suggestions guys! Also after I upgrade it do you think I can support vista?

http://www.amazon.com/Dell-Pentium-Dual-Core-Processor-Widescreen/dp/B002RKGDS4 here's the link of the computer I got