Integrate Php Script Into Joomla/hikashop

I have an upload script that I need integrated into the Joomla shoping cart Hikashop.

I need for the process to be as follows:

1. User selects product they want to buy
2. User uploads their picture
3. User pays

The upload script is located:
http://qualitycanvasprints.com/imageupload/

To see the ordering process:
http://qualitycanvasprints.com/order.html