Hey danyl1967, one thing that I didn't mention in your other thread on wireless planning is that your router/wireless controller should support AP load balancing with the number of clients that you anticipate.
If a school bus unloads and one AP suddenly goes from 10 to 40 users without any load balancing the results will be poor. Load balancing will automatically force a number of connections that exceeds your desired number to a secondary WAP. (Google wireless AP load balancing and you will get a good handle on the issues).
Also, not that you need to buy Cisco, but if you have a local Cisco dealer, you might get them out there to give you advice and an estimate on the cost (at least using Cisco) of a reasonable solution for your wireless network.