You have a 150 host network set up peer-to-peer? Ouch, I feel for you. I'd start pushing for some form of central management. It would mean some up front time and effort, but on the back end your life would become much easier.
Perhaps block streaming sites for student computers, and less restrictive access to the teachers. Set up some form of request system to have a site unblocked with advance notice if the teacher needs it for a lesson. Teachers should know in advance when they have need for multimedia sites, it's why they keep lesson plans.
Me, i'm a little more hard boiled, I wouldn't bother with hearing complaints about streaming sites without a very good justification for needing them. I'd want to see a lesson plan requiring it.
Train your teachers how to download a youtube video so they can present it offline.
I'm harping on youtube and streaming media because they are total bandwidth hogs. Doing some back of the envelope calculations, consider youtube's minimum bandwidth requirements of 500 kbps and you are looking at 25 megabytes per minute. multiply that by a class size of 33 students and you are looking at 750 megabytes for just one minute of video. This is just for youtubes minimum video settings. That would eat up your bandwidth very quickly.
As for patches, you can get all of them from microsoft's support website, it's a pain to do so, but one download and a trip around the campus would cost you footwork, but gain you some bandwidth savings.
My thoughts, get centrally managed as soon as you can, so you can push updates out from a central server, and block media streaming websites as strictly as can be allowed.
