Will I be able to play games on my computer?

Hi, I have an older pc like three years old and I wanna do an upgrate. Ram from 512 kb to 2 gb, video card from radeon 9550 to agp ATI 3850HD however my proccessor is an AMD sempron 2.8 ghz, my harddrive is 320 gb. So my question is if I would be able to play some of the newer games like issins creed even If not smoothly, providing Iam not gonna buy a new PC for now. Please give me an advice. Thanks.