Code two simple payment buttons (FFpay)

We have a PHP online shop built and coded and database driven: [login to view URL] All we need is for someone to create two payment buttons for the final step in ordering items from the website. It will be very helpful if you have worked with Paypal and/or Google Checkout before as these are the two merchants being used. I have attached a spec sheet explaining what needs to be done. You will be given full ftp and cpanel access. Feel free to ask any questions.