I need information on how to replace, what type and where to buy battery. We are bracing for "Frankenstorm Sandy" here on the east coast. We live in Wise, Virginia, extreme southwest Virginia, where we are expected to have blizzard conditions, up to 17" of snow or more. Power outages are almost imminent in many places, I need your immediate attention on this matter. This is our first time using it & are looking forward to having heat for our sick mother and brother.