Client Management and Calendar Tool

Basically the site is a tool for me to manage my business. I am a Massage Therapist, I want to have an online calendar where clients can view my schedule and request an appointment and even pay for it in advance. In order to do so they need to create an account with contact information. The calendar would need to be configurable based on selectable products, for example a one hour massage would block out an hour plus time to reset the linens etc. That buffer time would need to be adjustable. On the backbend I would need to be able to manage all the clients, see their history, be able to add notes after each appointment and be able to send them periodic email for marketing and appointment reminders. I already the graphics designed so no design work is needed, just development. I would like it to be clean code, that I can be added to and changed in the future if needed. Additionally I would like to have the copyright to reuse the code. I am in a bit of a hurry on this, I had already hired another developer but he took my money and never completed the project. So time is a huge factor for me on this.