1992 Dodge Dynasty Slips

First thing, I am unemployed and can’t afford to take this car to the shop. My wife and I had to buy another car, which is a Dodge Dynasty Mfg date 8-92, with a 3.2 Liter V-6. A friend of ours whom we bought it from. Said it started to make a noise and she parked it right away. Her husband changed the transmission filter and added fluid. When I went to pick it up, she stated it would not move, but it started great. I decided to tow it home. The first thing I checked. Was the transmission fluid, and low and behold. It was overfilled to the hilt. I called her husband and asked about the filter, and he said it clean and there was no metal shavings in the pan. I drained the fluid to recommended level and started it to take it for a drive. The car will not move unless you rev the engine up and bam, it takes off, tires squealing. All gears work including reverse and drives great, but you can’t bring it to a complete stop, or you have to rev it up, for it to catch the first gear. If you slowly roll through a stop sign, and apply the gas as normal, no problem. Right now it’s just to dangerous for my wife to drive it into town, and get behind someone at a red light for her to gun the engine, and for it to take off, hoping the person in front of her won’t hit the brakes. Like I said it’s a great running car, it’s just you have to gun the engine to get it to go from a dead stop. I spoke with a few shade tree machines and they said it was a sensor, is this true, and is there a way for a poor boy to fix or bypass something to make it work. Please help