Upgrade my video card for hp pavilion 9357

What are the specs of the system?

Just looked them up.

What is your budget?

Don't want to get crazy, would like to stay below like 150.00. If I were going to spend more I would do more upgrades. I was told else where that I should upgrade the processor. Haven't looked into the price of that yet. What you think; do I need to do both? The pc seems to run pretty good just messing around on the internet, but I play wow, and it lags so I've been playing it on my laptop. (which I am not a fan of doing).
Thanks for any input...