Sidebar and Main Content Div text overlapping in browser

Hi there,

 I am trying to recreate a website similar to this one:

 http://www.parisihavens.com/index.php

 I am working in a HTML file but should I be working in a PHP file?  Also,
when 
I place a table in the sidebar and preview it in the browser it looks fine
but 
when I reduce the size of the browser window, the sidebar div and main
content 
div overlap.  Finally, I'm trying to place an image into the header table
but 
it's not working correctly.

 Can anyone help me?

 Thanks!