Put extra banner space into header.php

Hi Everyone!

Maybe i´m trying to do something that´s really difficult, but I need to do it in one way or another.

What I´d like to do is to add extra banner space into my theme to be able to put in advertisement.

If you look at my site: http://www.bloggmorsorna.se

I would either like to have the extra space above my own header, same size: 1100×60 , below it, below the menu and over the headline for my posts. (in one of these spaces, prefereably above my own header.)

I wonder if there is a coding i could add in my header.php to realize this?

Thankful for help / inputs!