BMW: Head Gasket leak and my 2001 325ci Convertible, blown head gasket, head gasket leak

Question
Josh,
I am in need of your expert advice and opinion.  I am in the middle of a fight that involves me, my car repair facility and my warranty insurance company.  Let me cut to the chase, I found out last week that the head gasket on my car is slightly warped.  The claims adjuster and the insurance company is stating that the head gasket became warped because I negligently drove the car while it was overheating.  To my knowledge this car which I have owned 1 month shy of a year has never overheated.  I was informed upon taking it to a certified BMW repair shop that there is a slight crack in the Reservoir tank.  When I took the car into the shop it had coolant in the radiator, so I am not sure when it over heated.  I am really searching for other possible causes of the head gasket warping.  Any advice or information you can give me to prevent me from having a heart attack over the possible cost that I may have to bear if the insurance company refuses to repair my car.  Also, where can I get information about purchasing a low mileage engine, in the event that I have to replace the one that I currently have?  

Answer
Kristina,
 Give me more information on how/why you went to the insurance company in the first place.  

 You said that you have a warped head gasket, but how did you find this out?  Something had to happen for you to bring the car in and have it checked.  When they checked the car they found a blown head gasket because of a warped head.
 
 I just want to get all my facts together before I can make an educated estimate about what you are going through.

 I have dealt with adjusters as well.  They want you to think that they are your friend, but all they are doing is trying to get out without spending money.  He will go to the ends of the earth to prove that you caused this car to over heat, and that they are not liable for the damages.

 Get back to me with the details about how you noticed the car had a problem, and how you found out that it was a warped head gasket.

 Thanks,
 Josh