This place  is well connected to all parts of Mumbai by train, Bus and auto rickshaw. 

Bus
Click on the link below to check out the buses that BEST runs. You may find a bus that will drop you close to your school!
http://www.go4mumbai.com/Mumbai_Bus_Route.php

Train
Click on the link below to check out the Mumbai local train time table.Sion lies on the central line . 
http://www.go4mumbai.com/  

Auto Rickshaw
Click on the link below to check out the Auto Rickshaw fare card. 
 http://www.taxiautofare.com/taxi-fare-card/Mumbai-Auto-fare