Alternator/generator/regulator problems of the 2009 Lexus IS250

A year or so ago my car started overheating. I stopped and the car shut off. The computer system froze and said checking system and showed a drawing of a car frame and what I guess is the heat source. I took my car to the mechanic and he replaced the water pump. It had cracked and boiled over and ever since I have had nothing but problems. I've replaced the alternator, the battery, and my navigation system is blank and completely doesn't work. Nor do the buttons around it. The motherboard is fried. Also sometimes when I'm driving at night my headlights turn off in the pitch black driving down the road. My dashboard is melting and since I'm a realtor who puts a lot of miles on her car, I'm underwater. I'm either going to have a heat stroke driving that sauna around (the heat is stuck on) or crash when my headlights suddenly stop working. My daughter is learning to drive and I cannot let her drive once it gets dark. It's okay for me to die but not her. There doesn't need to be a sensor right under the water pump that can destroy your hole car. Thank you for your time.