Problems with veiwing "Fullscreen" theme at various resolutions

I am having problems with my website being available to people viewing it at various screen resolutions. I am using the “fullscreen” theme from Graph Paper Press. I work on a Mac with a screen resolution at 1920 x 1200 and can see my whole website just fine with everything centered and at correct proportion. However, people viewing my website with smaller resolutions see my website being cut off. Drop down menus are being cutoff and some of the pages are coming up on the screen aligned left instead of in the center. The home page has no scroll bar, horizontal or vertical, that people could use to get around the problem.

When I change the resolution on my laptop to 1024 x 768 I can easily see the problems and can not access half of my website, menus, or properly see my Soundslides galleries.

Is there anything in the appearance editor I can do to cater the Fullscreen theme to users with all screen resolutions?

Here is a link to the website: http://jhargrovephotography.com/

Thanks for any help!