Need a paypal connected to my forms

I have an html landing page which was built with pixbuilder. It's pretty much standalone with all it's own css and js etc. Anyway, there are several buttons on the page that trigger a form which collects buyer info which is then mailed to us. Anyway, instead of that action all I want to do is change the form slightly so it's a buy-now form with the same fields (different title) and the buy now button connected to paypal.

Paypal:
Item: £20
They can buy more than one.

Notification URL: www.groomarts.com/openday/pix_mail/paypal_ipn.php
Cancel url: www.groomarts.com

Can you do it and what's the charge?

I'm attaching a zip of the offline landing page with all the bits so you can see.