James,
I would suggest using a web form and hide firstname,last name,email and put a snippet of code (email me if you want the php or script version) to pre populate the hidden fields. Then on the web form also have a checkbox that's pre checked with an action to create an order (the upsell product) and charge the most resent card on file(the one they just used in order form).
So basically,
Create a upsel sales page that they go to from order form with only a pre checked check box and a submit button. All the other info is a pre populated hidden field.
Hope this help.
Steve
http://www.Infusionpros.com