Cross Browser / Mobile Compatibility and W3C Validation

We require this work to be completed within 12-24 hours of selecting a Freelancer. 1. Our site seems compatible with Chrome and Firefox, but not so much with Internet Explorer. We need our website to also be compatible for IE7 and upwards AND in IE Compatibility View. 2. Our website is almost mobile friendly, but it needs to be 100% mobile friendly. There are a few instances where the website isn't displaying content properly on smartphones, such as iOS and Android devices. 3. We also require that our website is 100% W3C Validated. The website in question is: [login to view URL]