Q: Shifter independently shifts to 1st and car jerks forward

While driving in town and having been in stop-and-go traffic for a while, my car’s transmission begins to have trouble. The shifter will independently shift down into 1st gear after I have come to a complete stop and the car jerks forward. Because of this problem, there have been times when I almost rear-ended other vehicles. The Audi S-tronic transmission has a well-known problem where the oil in the mechatronics unit heats up and causes problems with the circuitry. My car has already received a software update which cost many hundreds of dollars and it did not fix the problem. Now, if the transmission has been damaged it will mean multiple thousands of dollars! Can you give me any advice as to how to fix my car without having to borrow money to get it in good running condition?