I don't have much cash to put toward a new system but looking for advice on what I can upgrade on my system to get my game play somewhat less laggy. Which is currently almost playable. Which of these is best to upgrade for faster game play:

These are my specs:

Dell Vostro 330 All-in-one
Intel HD Graphics Card
Intel Core I3 CPU M380 @2.53GHz
4GB Installed Ram (2.93 Usable)

On a side note, I'm sure it's probably not worth it to Frankenstein this pc into something else but from what I can gather on Amazon a new graphics can is about $30, the I5 I can get for about $150 and 4GB of extra ram is $50.

Can one get a good PC for $250?