Where should i upgrade my ram?

What i mean is where should get it from? I currently have 4gb ram. I have a lenovo h520. 3.0ghz HDD is 1t and is win 8. It supports 8gb max.

http://www.tigerdirect.com/
http://www.newegg.com/...ewegg.com/
2 decent sites to get electronics from.
You could also go to Amazon, or any local electronics store if you don't like getting things shipped to your house.

Frost that wasn't the thing. I can't seem to find a ram that actually works for my computer or fits.

I recommend Newegg.
I've been using them since the 1980s when they had physical stores called Egghead Software.