Upgrade Paypal IPN

I have a working database and paypal integration. The paypal page currently sends and email to the customer (with a password) once the paypal verifies the payment. It then moves a row from one table to another in the database and displays a page which says order complete. I would like to upgrade the database search page: [login to view URL] I would like customers to be able to tick a box next to the row and proceed to purchase through paypal by clicking an add to cart button. I want the paypal page to send the multiple names and passwords ordered instead of only taking the single order as it currently does.