A good source of info about what this attack is and how serious it is can be found at
http://www.educatedguesswork.org/2009/11/understanding_the_tls_renegoti.html
It seems to me that it would not be that hard to just replace the code that is a problem
There is the question of what you should do, and what you can do.
Apple tries very hard to keep their iphone locked - it was designed for that. They failed. And continue to fail. The mac book was never designed to withstand the incredible hacking power of a team of grade 11 students. What makes you think you can lock them?
Given they are going to get unlocked, you might consider the most cost effective thing to do is just do the minimal thing to CYA and don't spend a lot of time trying to go beyond that. These students already have access to facebook, trying to stop them from using facebook is just going to make it worth doing.
I've seen bittorrent used for several business critical functions. One example is world of warcraft distributing updates using it.
The hardest part of climbing the ladder of success is getting through the crowd at the bottom.