Ok you have a js error on the front page which is stopping the bg image from showing. If you disable your plugins it should come back, then you'll need to turn each one on, one by one to see which is causing the problem.
To get your logo/top banner to span the entire width of the site you'll need to use a css solution and change the set up of the site to 'full width' sections in the layout editor.
Once you've done that you'll be able to remove the logo you've uploaded from Pagelines>site options>website setup. Now you'll have a page with just the back on etc.
Then you'll need to apply a background to the header are of the site using css. If you've not used css in the framework before please check out -
Basically you'll be giving a new instruction to the header area using the background-image instruction.