BMW Repair: battery light & radiator light, head gasket, cylinder head

Question
328i 1999, 56000 miles.  I was driving about 60 mph for about an hour and I stepped on the gas to pass someone and my car made a funny noise.  The battery light came on immediately.  The radiator light came on after about a half mile.  I parked it after a mile.  As soon as I turned it off, I think it was the radiator that blew.  Smoke was coming out from under the hood.  Do you have a diagnosis?  How much should I expect to pay?    Thanks.

Answer
Mr. X, It sounded as if your drivebelt broke or water pump seized and the belt threw. Expense is all dependent on how far you drove or how badly your car overheated. Definitely replace the thermostat when you do your repairs. Hopefully you didn't blow a head gasket or crack the cylinder head.
good thing you pulled over. You may have saved yourself bundles of money. I hope for the best.
-Evan