How to clean up backgrounds in Photoshop CC?

[JordanAlyse]

I'm a complete beginner to Photoshop but I needed it mainly to enhance and edit this picture, I can not seem to figure out how to clean up the background. Obviously I'm not good at any of the techniques I've tired. Can anyone on here give it a go?
http://tinypic.com/r/bfrn1x/8

[JordanAlyse]

I've tried placing a new background behind it which only looked choppy and unrealistic, I've tried gaussian blur, and the clone stamp tool to no avail.