http://www.newegg.com/Product/Product.aspx?Item=N82E16814150688&cm_re=The_260x-_-14-150-688-_-Product
I found this whould this help the performace of an amd apu
Well what APU do you have?
If you have say an AMD 7850k then you could run a 240 or 250 in Dual Graphics mode.
Any other APU or any other graphics card you can't do that with.
That being said no matter what CPU/APU you've got, you can drop in a dedicated GPU in increase your ingame performance.
The 260X is a little meh. Spend a bit more and get a 750 Ti, R7 265 or even an R9 270 and you'll be getting a lot more bang for your buck.
What PSU do you have? If it is crappy you'll probably need a new one.
I have an AMD a10-5800k trinity 3.8 GHZ and i have a Thermaltake earthwatts 80 plua certified 500 watt psu also what about this? http://www.newegg.com/Product/Product.aspx?Item=N82E16814127763
Don't get anything below a r9 270 or 265 or nvidia 750ti. Lower end products have terrible price/performance ratio and the improvement you see with crossfiring your APU can be surpassed by a better single card.
I do not believe you can run dual graphics. Grab an R7 265(preferably), or if it is too expensive, go for the R7 260X.