I read your OP and my conclusion to your problems leads to the use of cheap chinese parts and letting your wife drive your car. Both problems accrued when she drove the car, not you.
Your squeaking is due to a bad bearing in the idler or tensioner pulley(that is only if the belt is good and doesnt have any cracks in it). $30 (thats the price for an OEM pulley) and its fixed.
What you should do is invest $100-250 into some diagnostic software that will let you read and PROPERLY understand your 15 year old BMW.
I also fail to understand how a mature man with a family neglects such basic and simple things like a AAA membership when he drives a 15 year old car.