Would any one tell me which hardware to upgrade
I have a decent amount of cash from which I can buy one high end graphic cars or RAM or processor

My specifications are
1 AMD athlon 64 processor 3500+ 2.22 ghz
2 RAM 1 GB
2 windows vista
3 nvida geforce 7600 gs

Please answer because I want to upgrade it bf4 chritmas

If it were me, I would definitely upgrade the RAM to at least 2G - maybe 4G if possible.

The rest depends on what you want to do with your computer.

You might want to upgrade the video card to a new 8 series NVIDIA so that you can get the benefits of DX10 on Windows Vista. The 7600 isn't bad though, so for gaming it's probably still acceptable.

I agree on RAM