Please help

Hi i am wrighting to ask why my pc wont run new games smoothly my pc spec are CPU: core 2 quad GPU: nvidia 9600gt 1gb RAM: 8 gb 1333mhz HDD: 1TB OP: windows vista sp 2 now i know my pc specs are not very good at all but i would expect them to be better i got this in 2008 and have only just aquired the taste for pc gaming now i would like to be able to run gamessmoothly on decent resolutions. the frustrating thing is i can only run games like farcry 3 on 720p low GFX and get aroung 25-30 fps with the occasional framerate lag and freeze. the worst part is thats when i cranck up my graphics card to the top in core and memory clock speeds it can take before crashing. i would like to be able to run it on 720p medium settings some low at 45-60 fps like consoles can any one help any advice would be appreciated