[Theme Torch] add footer banner

As you can see, I have manually inserted a banner at the bottom of each page (except blog, of course).
http://sandrajackson.biz/
Is there a way of doing this, via custom css, that I can add the banner on every page, across the whole width of the page like the header, instead of installing manually – spacing is becoming a problem? The image is http://sandrajackson.biz/wp-content/uploads/2015/01/SJ-biz-banner5-e1422740385182.png

Thanks for an help you can provide…