Best GPU for a A-10 APU system?

Ok, so I have built the updated 350$ gaming pc that logan reccomended here (http://teksyndicate.com/videos/build-best-350-gaming-pc-nov-dec-2012). I was wondering what GPU I should get with it, keeping in mind that I will probably upgrade the motherboard and cpu in a year or so. I was thinking of maybe getting a 7870 OC'd, because its about 240$, and that seems to be the best bang for my buck around my price range (below 250$). My build has a 500w psu, and I was wondering if that would be enough to run this gpu and my apu at the same time, as well as if there is any way to use both the gpu side of the apu, and the dedicated gpu at the same time. 

 

Thanks

Welp since you boned yourself CPU wise by getting an APU and FM2 mobo, I'd suggest getting a 6670 and crossfiring it with your APU. No point in buying an APU then getting a dedicated graphics card.

Crossfire that :D

http://www.newegg.com/Product/Product.aspx?Item=N82E16814121442

I disagree, get a 7870 if it is in your budget. It will give you much better performance than 6670 in crossfire. Just because the A10 has an igpu doesn't mean you have to use it.

AMD recommends a 500w psu, so you should be fine.

Thanks for the advice, as I am planing to my next upgrade after this GPU to be a new cpu and mobo, (any suggestions?) I think I will just use the 7870 as the dedicated graphics card.

Thanks Again!