Plenty of Warning lights, car not starting... Hybrid battery failure?

Hi all, this is my first post here. Here's what's up.

History: My wife's Gen 2 Prius, 195K miles, has a bad touch screen display and the fuel Gage doesn't work right. It has run out of gas twice in the past few years and several warning lights came on when that happened (red triangle etc and others). The dash display Also has malfunctioned last winter.

My current big problem: the last couple days the warning lights have been on more frequently. Today it would not start. It would go into acc mode but would not go to ready mode and the LED on the power button wouldn't turn green with the brake depressed. So after looking through this site for so many hours, I tried pulling the negative wire from the battery for a few minutes, reconnected it, and it started right up. The warning lights were all gone and it was running pretty well and I drove it for about 10 miles and turned it off and on a handful of times with no problem. I stopped at the in-laws and halfway through my drive home the warning lights came back on (red triangle, check engine, brake warning, and red car with exclamation point on the display screen). The car also suddenly lost speed and would not accelerate properly. It would barely hit 35 mph with the pedal to the floor. I also noticed that the fan from the backseat seemed louder than usual. After a lot more research on this site I feel now like it may the the hybrid battery failing. Any confirmation on that or other ideas on what it may be would be greatly appreciated! I'm really hoping it's not the hybrid battery... I haven't had the best luck with Toyota dealerships accurately diagnosing the problem (they convinced my wife to get a new 12v battery installed once when she just needed gas and refused to refund it...) so that's why I haven't gone that route yet.