When you're in a WiFi area, go to your "Manage connections" settings. Thereafter, do a manual "search" for wiFi connection.
Your search results will show up if there is a strong connection available to connect to. If so, a green circle will appear next to a connection. Once you see this, go to the "options" menu (the BB sign near the track pad) and "save connection". Thereafter you can keep it activated whenever you are in school as it would be saved in your "saved WiFi connections" folder.
However, once you're home or in a non-WiFi connection area you will not be able to pick up the connection and under this circumstance you will need a wireless router.