Add one time payment processing to yii 1.1

Need a paypal module for yii 1.1. Yii will send values to the payment module to know how much to charge. The payment module should prompt the user to pay using paypal or credit card on paypal. User should have the option to allow payment to be processed when a billing is generated so that it can be paid without interaction. User should be able to cancel auto pay. No credit card information should ever be kept on the site. You will develop in your own environment and work with our dev who will implement your work on the customers server. We pay half when we see things running and the other half once everything is debugged, working and we both agree. Again, this must work on yii 1.1. Once we have done this, we will continue calling on you for updates and additions if this project has gone well. We may also have other sites and services where we want to add paypal.