Displaying a form on product page

Hello,

Newbie here so please excuse my lack of understanding. I have a wp-ecommerce shop, also i have a javascript which does calculations as in this one here>>>> calculations

I have tried to understand posts that have been written about implementing these codes but get lost after a while. I want to know if there is anyway i can add the calculator javascript to my website and how do i dictate where it should go.

All help is very much appreciated.