Background issue

I am using wordpress 3.8 and i really need to change the site tile color (Nationwide Seamless Gutters) or even add a header.

Also i would like to add a background color or image =.

Can anyone help with (what i am sure are real rookie issues)

and its on this domain as im waiting on a transfer so i made it live so you can help please veterans!!

http://pcandlaptops.co.uk/