I need Header Picture Background – Entire strip – Cant implement

the website is http://www.torontotrainingservices.com

If you see at the top there,… the whole header section…. where it has the log and personal training.

Well essentially all of that BROWN block I need replaced with a picture.

Unfortunately, wordpress allows me to add a header photo; however, it does not cover the entire brown block and is only a certain dimension.

Any ideas how to make my whole top half a picture.

I’ve looked in the style sheet. Hard