So this is what your two column lay out looks like.
I invite you to view the source of this page and see what I have done so you may copy. You will notice I have used a h1 element in the header, it makes sense to put a level 1 header in the page header. But I changed to font size so it what not quite as big. I like to do this because search engines give extra weight to text in it. As they do to all header elements. I also marked the menu up as an unordered list of links because that is what a menu is. But I removed the normally dot that is put next to link elements.
What I trying to push here is you mark this up as what they are. Then you style them. This helps people or things that can't see the page, like the Google bot and screen readers, to understand it better.
If you would like to you can download the zip file that contains an clean copy of this layout for your own use.