Tire Bubble problems of the 1999 Toyota Sienna

On 11/25/2012 at about 10:00 pm, after driving on freeway for about 100 miles, the front wheel on driver side began to make a small noise and small vibration and later the tire warning light came on. I stopped by at a rest area and didn?t see any noticeable problem. Since it?s about 50 miles away from home, I decided to keep driving it and the noise and vibration continued. I checked the tire the next day and found it flattened. I fixed it with a tire repair plug, pump it and I found a bubble about 4-inch in diameter. I drove back to vineland Toyota in vineland, NJ on 12/7/2012 since the tire was only 18 months old and was still in warranty. After taking down the tire, I found, on the other side of the tire, there was another bubble in diameter 3-inch. I strongly believe there is a serious safety issue with this model of tires of good year. If I kept driving my vehicle for few more miles, the tire would explode and caused a serious accident!.