What parts can I upgrade to push my pc to its max potential?

[Falketh]

So a few years ago back in 2012 I purchased a pre built Hp and since I was unemployed and still in high school I did`nt have much funds for a high spec monster. Now however I do have a bit of money but not enough to build my dream PC. So im mainly wondering what components I should buy so that I can actually run most games decently on my pc.

The system specs in question
http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c03520531

 

[CTurbo]

You could add a better psu and better video card. You would probably need to fabricate a way to add an extra case fan or two though.