Thanks for the kind words. However, I’m sorry but there’s no way built into the theme to center the menu. This is a customization you’ll need to make to the theme. If you search the Internet, there are several different creative methods of centering items of an unordered list, although you find there is no real perfect solution out there. Everything is pretty hacky.
For CSS changes, it’s a good idea to use a tool like firebug or Google Chrome’s built-in developer tools to locate them and then put the edits either in your child theme or in the “Custom CSS” option on your theme options page.
Also, here’s a helpful tutorial on how to use Firebug – http://vimeo.com/20917974. The only thing I’d suggest not doing is actually making edits to the theme’s CSS files, as it shows at the end of that video. However, the video serves as a good introduction to Firebug and how it can be used to find what CSS is effecting certain areas of your site without ever digging around in any files.