[HELP]Crossbrowser ISSUE

I Really Need Help here,
I Have a deadline of a week for a website of a client of me and i cant get the template i use working in IE

The website is https://www.whitelotusdivinity.com/

It works perfect in firefox but in IE i Can’t see my header and the pictures in de sidebar widget show a ugly gray border around them.

Please Please Please Help me with this cause i don’t know what to do anymore