side view mirror problem

today on the way home from school my passenger side view mirror started falling off. The actual mirror bracket is still attached to the door but the housing is detached from the bracket at the top. I havent looked to hard at it yet because its too cold out for my patience but it looked like some kind of wire hook was holding on the bottom half and i couldnt tell about the top. I searched on here and saw a couple of people mention it before but no one said how they ended up fixing it. anyone have any ideas?