Add extra div or frame

Hi All,

I have a question regarding the structure of my wordpress. I would like to move the entire “content area” and the “sidebar” down about 100px and insert a banner of somesort below the “menu bar” and the “search box”. Anybody here know how can I do that or which template file i need to edit?

this is a picture of what i mean:
http://i51.tinypic.com/v6ntro.png

this is the url of site in case you want to look and see where i meant for the logo to go
http://www.saatiri.com

thanks alot