I assume you want it to stretch vertically.
Here are some examples of how to get a shorter column background to be the same height as another column, assuming that both are flexible in height (otherwise just give both the same fixed height).
See item 16 here:-
http://www.wickham43.supanet.com/tut...ackground.html
The background image needs background-repeat: no-repeat so that it doesn't repeat but then you also need a background-color to fill any space below the background-image if the div height is greater.
<div style="background-image: url(image.jpg); background-color: #123456; background-repeat: no-repeat; background-position: fixed;>Menu div</div>
which can be shortened to:-
<div style="background: url(image.jpg) #123456 no-repeat fixed;>Menu div</div>
Repeat both div codes for the lower pair of Affiliates and Latest Posts.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.