Hi, Try with the following basic steps for better internet connection on your Blackberry bold 9000,
1.) switch off your mobile and switch it on after 5 minutes
2.) Clear your Browser history, cookies, cache
3.) Browse through a latest browser
4.) Check the RAM memory
5.) Disable background running apps
You can check your internet speed from www.ScanmySpeed.Com before and after performing these steps. You will definitely see improvement in speed.

(If your school has fixed Signal Jammer, Then your internet connection may get affected.)