Main Menu Length on ipad

Our main menu shows up fine on a computer. When viewed on an ipad horizontal it is to long and moves down into main photo on each of of the pages. You can view the web page at http://www.allsmilesdentistrylincoln.org.

When you view an ipad vertical the menu changes to a square that you click on to view. Is there a way when the ipad is horizontal it could also display the square to click on vs trying to show the menu links? If so, that would solve the problem.

Thanks.