Problem with header image

I am trying to upload a header image but it keeps the title of the site overlayed on the image when it is in place. I want this to replace the header text. To fix for now I have had to remove the header text from the site title but this means tabs on the browser window do not show any titles then.

Also, I am struggling when using in Internet Explorer. The site will not load the page properly – on opening in IE 10.0.9200 the page loads with no header, and with a drop down HTML5 bar instead of the full menu. Also, the widgets on the right do not load correctly, but load underneath the page instead of the side. I’m guessing it’s loading in a mobile view. Is this something you can assist with too?

Unfortunately this is on an internal site at work so I am unable to show you any links.

Thanks.