Sorry for not getting back to your question earlier, but this request is not an easy one to do, and so I have been thinking of alternatives to get round the complexities of this theme header.
Normally it would be quite easy to do, but in this theme it's not because of the way the header is in two parts, and not only that, but the fact that the top header collapses if there is no 'logo' added. You also have the added disadvantage of the 'Login info and Lang menu' in the top right of the header to contend with.
Removing the Login info is easily resoved as you can always add a login block on the frontpage, but that still leaves the Language menu. But if youi don't use the Language menu, then that can go too.
So the only thing you need to do now is add a <div id="logo2"></div>
beneath the first logo div tags in your layout files so that it looks like this...
Then in the moodle/theme/brick/style/core.css you can add the following rule.
background: url([[pix:theme|logo2]]) no-repeat right top;
And providing you add an image named logo2.jpg (png or gif) to your moodle/theme/brick/pix directory then this should work.
Hope this helps?
Oh by the way I changed the title of your original post so that this discussion can be picked up in Google or other search engines. PHP on it's own does not say much!