CSS Website Modifications

I have an existing html page and CSS files. It's a very simple site design, basically a white page with a header and footer. I want to change just a few things like add some color in the header, some links and a container for an ad unit, add a background behind the body of the site that will make the body content stand out and add some color and another ad unit container in the footer area. So, not much really. I could probably figure it out but it will take me too much time. I have the design sketched out, see attached. I will send a more complete design and all the files etc. to the coder. You will need to test on your server and send me the completed files. Shouldn't take the right CSS and Site coder to do this simple job.