Unusual situation... battery or impatient driver?

Hello! I am a newbie and really appreciate all of the kind people and Prius experts to share their valued knowledge on this website! My better half just purchased a 2009 Prius, with 95,000 miles, from Houston City's surplus fleet, at auction. According to their clerk, their mechanics are very proactive about maintaining their vehicles. Unfortunately, the car sat for close to three months prior to be auctioned, due to the bureaucracy of auctioning their surplus cars.

Fortunately, the car started with no problems and had no warning lights. The car ran without any issues for close to 900 miles. However, after making a 15 minute stop at Walmart, I noticed that the master warning light, hybrid battery light and brake light all went off simultaneously, after restarting it. This is after I had driven almost non-stop for the previous 900 miles! About 30 seconds later, the brake light went off.

Prior to this (about 15 minutes before), I noticed the car having difficulty accelerating over some of northern New Mexico's steep 9,000 foot peaks... no problems before these high peaks.

After restarting it and for the last 50 miles homes, the car drove perfectly (despite warning lights on).

Two days later (yesterday), I unplugged the battery and reset the waning light codes. Since then, I have driven the car 50 miles without any warning lights or problems. Maybe, I am just being optimistic, but do you think that there is the slim possibility that the hybrid battery just needed to be recharged... or I am I just a fool for posing this thought? Normally, I would take the car to the dealer, but I am located about 200 miles from the nearest dealer and I am hoping that some of you more experienced Prius drivers would be kind enough to share their insight with me (I won't hold you responsible for your opinions). My problem isn't so much with having to experience the difficulties of dealing with a broken down car, as much as it as with my elderly mother who is depending on me/the car for transportation. Thank You!

 

Great input... I am grateful for your prompt reply! I will recommend "the boss" to purchase an OBDII Bluetooth ELM327, after this email. Otherwise, the auxiliary battery, 12 v battery and all of the the fluids (oil, inverter, main radiator... etc) are correct. However, the radiator's reservoir was empty, which makes me believe that there is a leak somewhere... do you think that this may have been enough to trip off all of those warning lights? Thank You!

 

Thank you for your prompt replies! Inside the cap is good & the 8 month/100,000 mile battery warranty expired 2 months ago