Joomla form and payment via paypal

I have a price calculator on my website for the cost of my services. The client can fill a form, the price is calculated then he knows how much he has to pay. He also knows how much he has to pay at the reservation and how much at the end of the service. (2 times payment) What i need: When the client knows the price, i need him to be able to click on a button that say i accept the quote, then fill a new form that recap the previous form and add some fields and then be redirected on paypal to pay the amount calculated by the first form. You can see the the price calculator here: [login to view URL] or [login to view URL] => Nos prestations => Devis gratuit.