How to make my headers contents full width

Hello,

I would like my sites logo and navigation to sit close to the edge of the screen and I'm not quite sure how to do this without increasing the size of the main grid container.

The problem with that approach is that it then also increases the width of my whole website which I do not want.

http://liverflushsupplies.com/

Any ideas people?

Thanks in advance as always!