Tire Blowout problems of the 2001 Audi Quattro

My husband and I own a 2001 Audi allroad which is equipped with goodyear wrangler f1 radial tires marked allroad size 225 r17 m+s rated. These are the only manufacturer approved tires for the vehicle. About a year ago I experienced a flat tire and the sidewall was damaged requiring a new tire. It took several days to obtain a tire and I was limited to driving on streets as the spare is not a full size tire and cannot be used over 50mph. On July 2, we experienced a flat tire caused by a nail and the sidewall of the tire blew out. We tried to find a replacement. The 3 Audi dealers in our area did not carry the tire, and after several referrals we found a tire at grand prix tires in costa mesa CA which had been ordered by a customer but not picked up. At the same time we were told there was abnormal wear on another tire which needed replacement so we immediately ordered an additional tire. When I checked on the status of the order on July 30, I was informed that the tires are on back order and will not be available for at least a month---which means that I am forced to drive on a worn tire. I contacted Audi's customer advocates who claim that it is a non-Audi part and that they have no control over it even though they admit that it is the only tire which can be used on the vehicle. They referred me to their supplier---the tire rack who looked into it and again told me that the tires are on back order from goodyear and that it will be a month or more to get one (a total of 7 weeks plus). Audi refuses to address this issue so I am requesting your assistance in resolving it as it has now become a safety concern due to the wear on the tire and the lack of any other tire for this model vehicle.