Pasting other code without proper information - how it work and how it will affect your website. Is not considered as good coding practice.
If you want to add that code in your website. I suggest you that you should create a file and an includes folder in your theme directory. Then, parse that include file from there. Using this way, you will have your website intact.
require_once ( get_stylesheet_directory() . '/includes/gravitywiz.inc.php');
And, please go to http://gravitywiz.com/support/ forum, and start a new thread for support. We can help you with WordPress only. :)