Zen Cart Calendar Application

Budget: Don't Know

We are a rental company that uses a zen cart based web site to place orders on our rental equipment.  We are looking to add a calendar to each unit (car, boat, motorcycle) for reservations on rental.  (i.e. - when you are looking at a boat to rent - a button that says 'check availability' the consumer can click on this button and it pops up a calendar of open days to rent.  The consumer can then select a day (or days) and continue to check out.  
One other function that it needs to do, is once their credit card is processed correctly, the days on the calender would black out.  
Please let me know if you have any questions or need additional direction to provide a proposal.  Please include a time frame to complete work, dollar value and payment methods and terms desired. 
Thanks for your consideration of our project.