i need some help

i have upgraded my pc and now i dont think im getting the most out of it some things might need changing….. heres the spec

asroc 755 dual vsta motherboard ?50
ati sapphire x1950gt
2gb ram
intel e6700 core 2 duo
psu not sure probably rubbish
300 gb hard drive

need some help sorting this out to play games mostly thanks any advice will be great