Display problems in IE 8 with HTML 5

This website worked in IE8 in my initial development (plain html/css) outside of WordPress. In WordPress it looks pretty bad in IE8.
WordPress: http://www.rainbowstation.org/our-programs/nursery-school/
Html/css page: http://anamidesigns.com/rainbowstation/new/interior-mainsite.html.

I'm using HTML5 and have added js and css to make it work in IE5.

Can anyone see what might be causing the issues? If you go to the home page in the WordPress version, it's even worse.

I'm not enthused about supporting IE8, but my client would like me to try to get it working.