You really really need a new GPU.
What's your PSU?
Open up your case and look at the PSU, there should be a sticker on it saying the max wattage.
Also, you've got a great CPU to work off of, we won't have any problems with bottlenecking.
Laptop. Hmmfph.
With $600 I could give you a list of parts that would easily be better than your laptop, for a gaming desktop for you, if you were confident in building one.