PHP coding / MySQL development

I want an online website booking solution with the ability to text reminders, sync to google cal, view/add/edit/delete customers, manage different schedules for different employees (distribute booked appointments to employee schedule) and have the ability to create invoices. Basically this does pretty much everything I need minus the invoicing and customer database ([login to view URL]). They also offer this invoicing tool ([login to view URL]) which contains a customer database. The problem is there is no way to link and seamless integrate the two solutions into one. The databases are completely separate. I need someone to do this. I would like to be able to invoice and book appointments for customers without having to re-enter their information on the booking side. I also would like customer info that book appointments to be displayed in my invoice list of customers. Basically I need the appointment scheduler back end control panel with a tab added for customers and invoicing. I need the two products merged into one seamless solution. Please provide a quote and the estimated time frame needed to complete this project.