I have spent $1200 trying to fix the electrical problems on my 2000 VW New Beetle Turbo. Can someone help me?

Here's the problem: Sometimes when driving (about every 4 trips over 5 miles), my EPC light comes on and the car starts to run sluggish and usually won't go over 40mph and that takes a lot of effort. Sometimes the Check Engine light comes on too. The Autozone error code was for the TPS when I had it checked once but Hewlett VW in Texas said that there was nothing wrong with my TPS. If I turn the car off and restart it, it sometimes will temporarily fix the problem. Usually it does not and I have to park the car for about 2 days before it will run properly again. Also, the AC will lose power (it will be on Max AC full blast and then change to the lowest setting) from time to time. This does not happen at the same time as the EPC problem.

I took this to a VW dealer in North Texas and they replaced the digital water pump and some module (can't remember which) and the total was about $600. The car ran fine for about 3 months and then the same problems started again. I took it to Hewlett VW dealership in Georgetown, TX. They said that it was either the wiring harness or another module and that the wiring harness should be replaced first. They replaced the wiring harness and then claimed that they tested it and the problem was fixed so the module they mentioned would not need to be replaced. They said I could drive my car safely out of town. I did and the same problem resurfaced after driving for about an hour. I ended up having to drive on the access road between 2 major cities for over 60 miles because the car would not drive over 40mph. Very frustrating.

I'm scared to take my car back to Hewlett because I'm not sure if they can be trusted or if they know what they're doing. Since returning from my trip, I have driven the car daily for about 2 weeks with no EPC problems. However, today after driving for about 2 minutes, I pressed the brakes and something weird happened: the brakes pushed back as if they were controlling themselves and would not brake. I finally got them to go down. When they pushed themselves back against my force, there was a huge rattling noise from the hood and the AC turned itself on full blast. This was crazy because the AC was completely off at that point...the vent wasn't even on. So, now that my car is obviously not safe to drive on a short trip due to today's braking problem, I'm forced to get this fixed.

Has anyone had similar problems and do you think that the dealer can be trusted to change the module they mentioned? This is literally the last of my savings so I'm completely screwed in many areas of life if I spend it on the car and then end up with a car I can't drive. I know nothing about mechanics and no one I've talked to has had similar issues so I'm in the dark.

Thanks for any help!