Adding a script just above the comments section on posts

If you check out this article – http://so-sew-easy.com/3-methods-boxing-corners-bag/ Under the content there is a section headed up “Other blogs you might like”.
This is a script which has been added to all posts using a Plugin – WP Simple Insert which displays under content.
However I’m not happy with where this is displayed on the page and I actually want it to come underneath my ‘You may also like’ related posts widget and above the comments.

So I’d like to remove the plugin and add the script to my template/theme somewhere.

Except I have no idea how to do that. I’ve fiddled around adding the script into random places in my single.php and content.php files but can’t get the script to display and I’m worried I’m going to break the site with all my messing about.

Can someone help me with what file I need to amend please and where in the file code I need to add the script to get it to display in the right area, on single posts only. Thank you.