I have a very intermttent problem with my car. On some hills it seems to be something with the transmission, it hesitates and then revs kind of high loses power and then shfts and gets better. sometimes seems like it is a standard transmission being driven by a beginner driver.I am also seeing some hesitation when acclerating like getting on the highway. Once it settles in it seems to go okay, ie when it does not have to shift. But there is one really weird thing that happens randomly (even on flat stretches) and maybe once every few hours it totally loses power and wont go more than 20 mph even when the accleerator is floored, but it does not ever totally give out. And then it gets ok again. The intermittent nature of this makes it hard to diagnose.
Unfortunately, I predict that you will soon be stranded by the side of the road when that transmission finally fails. Everything that you have described should cause you to bring it to a transmission shop sooner, rather than later.
I strongly suggest that you ask friends, relatives, and co-workers for recommendations on independent transmission shops that have been in business for more than 3 years. More than likely, in view of the age of the car, you will need a rebuilt transmission, but you are likely to get a much fairer price and better quality workmanship if you go to a well-reputed independent shop and if you avoid chain operations like AAMCO, Lee Myles, Cottman, etc.