Aviation Invoice and Accounting Software

I need a program that will allow me to invoice my customers and keep track of products and services (mostly services, I only have a couple of products). I've searched for a program to meet my needs but very few of them are tailored to aviation. The programs that I found that were for aviation, were way too expensive. I have a very old program that is copyrighted and requires a license that I could show you as an example of what I'm looking for, as long as that's not breaking any laws. I don't want anything copied from it nor any copyright issues. The program will need to have at least the following: a customer database; an aircraft database; an employee database; invoicing / billing; a way to keep track of the time on the Airplane and the time the employee spent giving services (flight instruction); a reminder when the aircraft is due for yearly maintenance and when due for hourly maintenance at 50 hrs and 100 hrs; My employees are pilots / flight instructors. I need to be able to bill customers for hourly pilot services and flat rate pilot services. I also need to be able to know how much to pay my employees at the end of the week. I'm a very small operation, currently just myself, I may be hiring one employee this summer. I have only 2 aircraft for rent. So the program doesn't have to handle large numbers of aircraft, products, or employees, because I have only about 2 of each. Please let me know if you need any more information to make bids, Thanks.