Sidebar messing up between Firefox & IE!

I have been trying for over an hour different ways of fixing this problem. You can clearly see the error of the sidebar if you view my site (link below), in Firefox it’s working, it’s up right under my prepared ad spaces. However, in Internet Explorer, as you can see the ad spaces are in their correct spot, but the rest of the sidebar (categories, recent posts etc.) shows up all the way at the bottom of the page!!!

I have went into the stylesheet file and edited the float: for sidebar from left (which made the sidebar info show up directly under the posts in IE), to right which shows it up as it is now.

When I tried editing it to “float: top” instead of “float: right” it made the sidebar work correctly in IE, but then in Firefox it messed the sidebar up by making it fit so that it’s only like 1/4 as wide or something.

This is annoying, anyone have any ideas?

Site: The Amature Traveler