Okay, here is a manual captcha addon for the script.
I wanted to automate this and add it to the adminCP but I've obviously not got the time for that at the moment; so in any case, to avoid further delay, I put together this manual update that will add standard captcha functionality.
How To Install :
Read the README file
Short Version :
Upload the captcha folder to your domain
Upload the new index.php
Edit the style.css with the included declarations in the readme file
I apologize again for the delays as well as not automating this or having it in the adminCP yet.