Add calendar view to a Drupal Module

Hi, I have a project in progress. I am using the Rooms Module [login to view URL] and Commerce along with multiliingual website. Currently Rooms provides an availability checker that will return results of rooms available. BUT this does not display the results in a calendar just displays what is available. In the backend/admin you can see this information but it is intended for the admin not the end user. I need a calendar showing with bookings available and unavailable dates with a cross through them ....a bit like on this website. [login to view URL] and attached screenshot. The client wants this additional feature ...so I need to charge extra for it and am looking for prices. I have started with a low price...its up to you to prove the price if you think it should be more development time...I don't think so but...I am open minded!! Ideal would be a seasoned Drupler looking to add extra functions to an already good module.. All credits would be passed on to you should you want to submit this to the Drupal community afterwards. Thanks for your time . Alex