How can I upgrade my HP Pavilion p7-1010 to be better for gaming for $200?

[Alpa_Lord]

Hello, I currently am using my HP Pavilion p7-1010, and as such, I cannot play many games at a decent fps. At medium settings, Minecraft can only run at around 30 fps.
Here is the link to the specs page for the pc: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c02856262&cc=us&dlc=en&lc=en

I have not upgraded it at all yet. Should I upgrade it with a new PSU and GPU? If so, could I do it for around $150-$200?

Edit: I am looking to play games like gta 5, far cry 4, and saints row IV.

 

[CRITICALThinker]

This should work

PCPartPicker part list: http://pcpartpicker.com/p/R6yND3
Price breakdown by merchant: http://pcpartpicker.com/p/R6yND3/by_merchant/

Video Card: XFX Radeon R9 270X 2GB Double Dissipation Video Card ($149.99 @ Newegg)
Power Supply: Antec TruePower Classic 550W 80+ Gold Certified ATX Power Supply ($39.99 @ Newegg)
Total: $189.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-01-24 23:51 EST-0500

This will not however affect your performance in minecraft much, as it is dependent on a fast processor and memory.