Transmission and A/C

1997 vw jetta gl, 2.0L. I bought my car over a year ago and it is a very good car. I have 96,000 miles on it and recently my transmission will hesitate. When I stop at a red light my car will jerk it self into 1st, really hard and sometime into 2nd as well. My tranny is an automatic so I took it to the dealer and they said my tranny fluid was low so they drained the fluid and put new fluid into it. It worked fine for a few days then it started again. I looked under my car to see if it is leaking but I can't find anything wet. I do have mechanical skills, im a heavy equipment mech. In the marine corps. But I dont want to break something on my car and have to spend more money to fix it! One more hing is my A/C leaks watter out of the vents and my carpet keeps getting wet, also my vents will smoke a little bit when I turn it on. Any suggestions would help me out right now. Thanks