I removed the - [container class="four columns" (first child of #main container) in header.php file]. The postings and comments then occupied the space on the left where the navigation was. However, after editing the [(class="twelve columns" -> class="sixteen columns")] in the header php, the side bar on the right displaces beneath the postings and comments section at the bottom of page at sixteen columns, so I reverted it back to twelve. I then searched for all other instances of [(class="twelve columns" -> class="sixteen columns")] in all files and could not locate anymore.
Please advise how to maximize the postings and comments sections to fully occupy the now empty columns to the right of the comments and posting sections without shifting the right sidebar to the bottom.
Thanks again :)