Ok I'm a dolt . . .

I've done this before, I just don't know which file it is I need to work with. Please see the logo at the top of the page here:

http://www.sweetpeasbabygifts.com/store/

I'm wanting to do the same thing on a new site, but I can't recall what file it was I had to edit to make that image appear 'above' the 'home\logon' bar. I'm thinking it's the tpl_header.php file but I can't find that in my directory.

Any help is appreciated