Looking for advice on buying a Graphics Card

tell your whole pc specs and your budget

It is a decent mid-range card. Not the top, not the bottom. Your Power Supply is very important, 500W does not tell us enough the brand is the most important, sometimes the model. Especially when it comes to "stability". I don't know much about the power system in cypress but the power supply takes you local power a feeds it to your sensitive computer electronics. Not like light bulb or hair dryer which can flicker and be ok.

I have a SL-500a powersupply

The card is not the best for gaming but should be able to handle game fairly well. And yes a 500W power supply will be enough

For that price you can get more horsepower with 7750 and if the price is right perhaps 7770.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

A GTX650 will do fine. The 7750 is not faster on average, pretty much exactly the same. The 7770 is faster, but by barely anything - you can see it on benchmark charts but you wouldn't be able to notice the difference in the real world. None of these are really powerful GPUs, but they're fine if you're OK with lower settings.

If this
http://www.computeruniverse.net/en/products/90210243/in...
is your Power Supply, it's pretty much junk. Yeah you can run these, but you really should get a better PSU if you value your computer.
http://www.singular.com.cy/corsair-builder-series-cx430...
Would give you more usable power, even though it appears weaker.