Automatic Transmission problems of the 1999 Volkswagen Cabrio

I have had transmission problems since the car had 8,000 miles on it. You push on the gas and the car goes just enough to put you into oncoming traffic and then it won't go anywhere for 3-4 seconds. This has happened on several occassions. I have taken it to the dealership to fix twice and they keep telling me it's fixed, but it's not. My car now has 56,000 miles on it and is out of warranty. No one wants to fix the problem.