Help needed on final battle in Sorcerer's Stone for GameCube

[Becca]

I am completely stuck here. I spend half an hour trying to figure out what to do. I know to move when Voldemort/Quirrell casts "wingardium leviosa", but no matter what I do I can't damage him. One guide I looked at said you are supposed to "stand so you are connected to the mirror and wait for him to cast the spell... make sure he hits Harry directly... wait for Harry to glow green, then get close to Voldemort and hit 'Release'". I have tried that but it never works... for one thing how do you get close enough to him without breaking the connection with the mirror? Please help!