How to extend page menu background color across layout

I am a volunteer working on a nonprofit website. I am having trouble finding the place to add the background color for the page menu so it goes across the layout. The background color is 01928F. I want to change the dashed line around the page menu to solid also.

And how to remove the black lines above and below the header image. Thanks for help.

http://dev.aauwatlanta.org/wordpress/