Date Checker/Reservation Form

I would like a date checker/reservation page created much like this one: [login to view URL] The form for my website needs to do much the same thing as this form does. It needs to query a date for availability, indicate whether that date is available or not. Add prices up based on packages and options and the city chosen. Further, it needs to store data in an area which can be downloaded to an excel file so that I can use that data to populate my contract. The reservation button should connect people to PayPal to pay the deposit which will be based on the package that they choose ($200 or $500) and it should fill in the data that they have put in there so that they don't have to repeat it for PayPal. The form should get its date data from my Google calendar through an xml feed or ical feed. Otherwise, a simple backend program would have to be created to allow me to black out dates.