Tank Mounting problems of the 2007 Saturn Outlook

The fuel tank in our new (two day old) 2007 Saturn Outlook ended up with a hole in it, leaving a pool of fuel in my mother's driveway. We were being very careful, since it was a new vehicle and do not remember hitting anything that could have potentially caused the fuel tank to bust. After further investigation, pictures backed this up by showing no damage to the undercarriage of the car, less the busted fuel tank. I am concerned because the plastic fuel tank has no shield on the tank. My concern was further increased when an individual at the Saturn service shop in amarillo was trying to prove that the tank was strong enough not to need a shield when he punctured a similar tank by hitting it with a hammer. Is this tank safe or am I putting my children in a dangerous vehicle?.

When the gas tank is at 1/4 or less and the car is parked on an incline either forward or backwards the gas gauge reads empty for at least 10 minutes after the car is started. Since the gauge reads empty the car stalls once it is started or it doesn't start. When it stalls after the car is in drive I loose my power brakes and I am unable to apply my brakes easily and my children and I are put in a bad safety situation. I am unable to stop if something or someone runs in front of the car when it stalls. This is a 2007 Saturn Outlook. Saturn says they are aware of the problem however, I was told by them everytime I bring the car in to make them aware to see if a fix is available.