Recently purchase 07 with 131k

welcome! yes, winter. 43-46 is average. all the best!

 

Your MPG is fine. Hybrid battery is guesswork, but the available statistics suggest a failure rate between 3-15% after roughly 10-15 years of operation, with higher failure rates as the vehicle gets older, as it's subjected to prolonged high temperatures, and as it's subjected to rapid cycling due to mountainous terrain. If you mainly drive in the northern US and don't make frequent trips over the Rocky Mountains or Appalacians, your battery has a good chance of lasting another 5 years/75,000 miles or more.

 

Seems as though you got an excellent deal -- as with any used vehicle though, only time will tell. As others said, your MPG seem right-on.
Pick up an OBD 2 diagnostic solution (Torque App for your phone or Techstream for your computer) and you'll be prepared to tackle any future issues.

Welcome, and best of luck.

 

My 2009 that I just got (also in Michigan) got about 38MPG over the last 200 Miles on the highway.
This is driving the way I drive normally.
Simba

 

Yeah, cold wrecks MPG. If you look at the MPG graphs for the Prius on Fuelly, you'll see that people who live in northern climates have a yearly cycle: 35-40 MPG in winter, 50-55 MPG in summer, in between in spring & fall.

 

Drive and enjoy!