PHP Script. PayPal integration

I need to have a current Registration form integrated with making a PayPal payment. i.e. a client hits my site, signs up for membership, then has to make payment for that membership. The entire site is PHP and also has a MySQL backend. The site may be viewed at [login to view URL] Be sure to click on Registration and view that form. I need it so that if someone chooses the Basic Membership they will go to a payment screen in PayPal to pay that specific amount and same for Premium Memberhsip. Should be a simple project for PHP professional. Thanks, ALARIA