Clinic Appointment Scheduling App

We have the basis of a Health Clinic Administration / Patient Management Application. I am looking for someone to develop the appointment scheduling aspect of this. As part of the booking process an agent needs to be able to view availability of diary "Slots" in the relevant diary, they then need to be able to create a booking / allocate this slot to the booking. Obviously this "slot" is then filled and shown as busy. Ideally need to be able to drag and drop appointments. Need to be able to create multiple diaries and be able to administer these - ie opening hours, availability etc. Most of this functionality is already in SF and suspect we may be able to use resource / public diaries, need some help to pull it together. Preference for native SF.