Media Query for Droid 3, and forcing menu button up to 720px

I have two main issues to solve on prismatic-solutions.com/staging2/.

1) the navigation background images won’t fit on screens below about 720px wide. So I’d like to have the “Menu” button appear up to 720px.

2) Except for item 1, the site seems to work reasonably well on most devices I’ve tested. But on a Droid 3 I’m told the navigation breaks in portrait orientation. I have the background images for the colored navigation set to only occur on screens above 600px. Apparently, the Droid 3 thinks it is above 600px wide in portrait mode so it trys to display the nav background images when I don’t expect it to. Could someone suggest a media query specific to the droid 3 that would solve this?

(using twenty twelve w/a child theme)