move header image underneath site title (header text)?

I am working with a child theme of Twenty Twelve. I have moved the navigation menu below the header image following instructions supplied in another post in this forum (by modifying the header.php). Now, I would like to superimpose the site title (header text) and tagline on the header image (by moving the header image up and underneath the site title/tag text) AND, also, tighten up the space between the bottom of the header and the top of the navigation menu. How can I accomplish this task?