So i want to upgrade my videocard.

So about 3 years ago i bought the Accer asspire X3300 which is a budget pc. It used too do fairly well but now im
looking for a new videocard. I have got no idea how too go about this.
I would love a few tips.

you're pretty much screwed. It's a small form factor case which means you'd need a low profile card, which are rare and decent graphics cards do not exist in low profile form factor. The case would not be able to cool a decent graphics card and the PSU (custom, so not upgradable) would not support a decent graphics card. Get a new PC in a sensible form factor (mid tower or full tower).