here is what you do.
1) go to ATO->Style & configure SIDEBARS->RIGHT INNER sidebar: Display on: and turn it on for all pages or just the 'Single Posts' and make note of the 'RIGHT INNER sidebar WIDTH'
2) find the post ID number (edit the post and look at the address, the last part is the ID number)
3) add the following to the CSS Inserts
HTML Code:
.colthree-inner {width:0px; display:none;}
td#right-inner {display:none;}
body.postid-2460 .colthree-inner {width: 200px; display: table-column;}
body.postid-2460 td#right-inner {display: block;}
make sure to change the post ID number to your post and the width to your width