Looking to buy a graphic card for my new Desktop!

MFV

Honorable
Dec 28, 2013
3
0
10,510
So I have a Gateway DX4375G A6-5200 Quad Core 6GB 500GB Radeon HD 8400 Windows 8 Desktop PC.
Specs are:
Processor: AMD A6-5200 2.0GHz Quad Core
Graphics: AMD Radeon HD 8400
Power Supply: 300W
Operating System: Windows 8
Dimensions: 17.9 x 16.5 x 7.0 (L x H x W)
I was wondering what kind of graphic card I can put in here for it to run, lets say... League of Legends or another game at 50+FPS?