Database creation for mac possible ongoing project

I have a small business and take bookings for classes and courses, I need to develop a database or other system to keep track of bookings, customer information and other bits of information which will be useful - for example keeping track of which website bookings are made though, if I have sent a confirmation email and contact details. I would like to be able to sort the data easily by class and the class participants and always have the next upcoming class at the top.
I use a mac and so need a program which will be mac compatible ( I downloaded bento because I thought it would sync with ical but found it doesn't so returned it also I didn't really like the style of it!)
SO far I have been using a very basic excel document to keep track of my bookings and contact details which I have attached ( without the customer info). Its important to be able to keep track of class bookings as groups and to keep a record of information sent. Basically I am looking for a better, smarter version of what I have already.
At the moment I am only working with a small amount of information and I am just a start up so expensive programs are not really what I am looking for just now.
I am looking for somebody who will be willing to take the time to work with me to really understand whats needed and in finding/creating the best solution/ software to use and one which may be able to be developed as the business grows.
Please get in touch if you feel you would like to work on this with me, ideas and also an estimate to the cost

many thanks