How do I make this compatible with IE?

I have designed this site initially with css3, but it is not compatible with IE, particularly with older browsers.

Could help anyone help correctly code this for me?

Maybe this error is throwing a spanner in the works?

“Fatal error: Call to undefined function nzshpcrt_shopping_basket() in /home/clogsfor/public_html/wp-content/themes/shopme/sidebar.php on line 4”

Sorry forget about this thread, im just going to install another theme.