Improve the speed of my Desktop

Im Currently running a 550 Watt PSU and a Nvidia 610 1Gb and it just cant handle what i would like. Ive been looking for a new one but try to stay around $100-$150. Please leave the model you would reccomend and link to store if possible.

 

AMD FX-6100( Six Core, 3.2Ghz)

Nvidia GT 610 1gb

8Gb Ram

550Watt PSU

500Gb  5400 RPM HDD.

 

Im assuming you're not looking for a new computer, because you're not going to find one better than yours for that much. I'd suggest buying a 650, the EVGA version should do fine and comes with 75 dollars for F2P games. http://www.newegg.com/Product/Product.aspx?Item=N82E16814130828

http://pcpartpicker.com/part/asus-video-card-gtx650tio1gd5

you can get a GTX 650 Ti for as little as $129, but this one has a much better cooling system, since the 650 Ti happens to run quite a bit warmer than the 650.

 it just cant handle what i would like

and that is? please explain further what you can't run, or what do you want to run that it doesn't