Budget graphic card for photoshop?

[LightAngels]

My specs:

APEVIA ATX-CW500WP4 500W ATX Power Supply
ECS A885GM-A2 (V1.1) AM3 AMD 880G SATA 6Gb/s ATX AMD Motherboard
AMD Phenom II X4 970 Black Edition Deneb 3.5GHz Socket AM3 125W Quad-Core Desktop Processor HDZ970FBGMBOX
2 x PNY Optima 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model MD8192KD3-1333 == 16GB total

I don't know if it is enough to run PS6 in term of specs or not. But somehow my computer runs it kinda slow.
So my question is. Will it run significantly faster if I add a GPU to it? If it does, what is a good budget GPU should I buy that is compatible to the specs above?

This one is for my dad, not me. I'm using a 7950 on my comp

 

[spp85]

To improve the system responsiveness SSD drive is a great addition combined with an entry level GPU like this at http://www.newegg.com/Product/Product.aspx?Item=N82E16814161427 would make your Photoshop usage much smoother.......

 

[LightAngels]

Thanks!