I am sorry, I didn't get it: why do you need a "send from" box?
This is going into my payment page for BitCard. The send from box is where the customer enters their bitcoin address. The send to box would obviously be my bitcoin address. When the customer hits submit, it will automaticaly send the BTC value in the other box from the send from box to the send to box.
Not really sure what you meant with the rest, please give another example :x
Ok. Customer buys some items and clicks the checkout button. It leads them to the page I'm describing. This form has to be able to convert USD(from the previous page) to BTC, send me notification by email of the order while displaying a thank you page. This form also has to have 3 imput boxes. The first one the customer puts their address in, the second one has my adderss in it, and the third one is a value display from the previous page(where the conversion script comes in). Once the customer fills in their address and hits submit, the form has to send that value that's listed in box #3 to my bitcoin address to complete the transaction.