Conflicting CSS

Hi there,

I’m using the Responsive Theme and installed the WP Properties plugin. There is an option in the plugin settings that “Load Default CSS”. When this is checked, my website looks right except for the plugin content of course. When it is checked, the plugin data looks right, but it messes with my site – footer is aligned left, content doesn’t span the whole width.

I’m very new at this. I think there is a conflict in the CSS, but not experiences enough to know for sure and how to resolve.

This is the link with the plugin setting to load default CSS.
http://www.derekkaufman.com/rentals/

I appreciate your help.

Derek