The logo container will need resizing by changing the class on it as well the navigation container (which sits just to the right of the logo container. This is where you will need to install the included child theme so you can make these kinds of changes and still have the ability to update the theme itself (the parent theme as it would be called).
The logo container in the header.php file has a span4 class and the navigation container has the span8 class. You would need to make the span4 a span5 and then the nav container span8 as span7 (this is so that both equal 12 (long story).
To use the child theme, you need to install it, found in the theme files in a folder called child-theme. Then copy the header.php file of Celestial Lite into it where you see the style.css, then make that change I mentioned to that one.
