1998 Volkswagen Jetta

I have a 98 Jetta and I have had a few problems since I bought it three years ago. I am in the military and before we went on our deployment I noticed a small transmission fluid leak. I was unable to take care of it before we left and while I was driving it the car would run fine but would just cut out when I got up to about 25 mph. Once I would let off of the gas and push it again the car would run until this once again happened. There have been times that I have had to leave my car sit for months at a time in Washington state weather. I know this causes problems but the car does not have a lot of wear and tear on it, only small problems. I was wondering who would be the best person to take my car to and how long it would be to completely fix it. Any help would be appreciated.