Changing header container from color to image

I’d like to change the look of the heasder in my site: http://bc-plusapp.com

When I set the header image, the image goes above the container where the logo and the menu go, it is a white container called “container-sony”.

I want it to have an image instead of just being white. Here’s a screenshot:

http://bc-plusapp.com/wp-content/myimages/BC-Plus-Courier-Pgina-principal-_-BCPlus-Courier.png

How can I do this?

Thank you