Change header

I am using the Atahaulpa theme. I wanted to add an image in the main header. I am aware that there is a logo (called logo.png) in the header- that change was simply changing logo.png in the header.php file to newlogo.png. However this is not what i am speaking about. There also is a Title and a tagline in the header, to the right of these I wanted to add the image (in this case a jpg or gif file ) Each time I do a search on header image Atahaulpa I am referred to the admin panel where you can change images but they seem to be in a sub header which is below the main header that I am speaking about. The method apparently must be related to adding code in both the the header.php and css files. Has anyone implemented this.