How do I expand this on the skin?

[Dominican Airways]

Hey guys so I was working on my site when I was trying to make I guess you can say my site's width bigger. I have some of examples of what I am talking about. I would like to be able to add a different color image behind where all the words on my site are. Very confusing I know the example picture point at what I am trying to get to

Example One: http://i.imgur.com/N7xPQ.png

Example Two: http://i.imgur.com/ub2Xe.png

[Stealthbird97]

Increase the width of the container.