CEL P1038 and Cold Weather

Hi all,

I have a 2007 prius, approximately 210,000 miles. This past week my CEL light came on a couple of times. I kept intending to drive by NAPA to get the codes read, but then the light wouldn't be on. Finally today, it came back and I went by NAPA and they got the error code P1038.

I have spent some time browsing other posts:
P0138 Code help! | PriusChat
Another CEL Thread!!! P0138 and P2195 | PriusChat
Oxygen Sensor Code and Cold Weather | PriusChat

It seems like there is some suggestion that cold weather can cause this. This is my second year living in Gunnison CO which is quite cold in the winter, regularly below 0 degrees F at night (-11 F tonight!). I don't have a garage and I commonly drive through loose snow. Would anybody have suggestions for things to try and check if it is the weather/snow issues rather than the actually sensor having failed? I'm wondering just because other posts noting cold weather issues and the fact that the light hasn't come on very regularly.

That being said, it was fine all of last winter with the same type of weather, and I have noticed that it smells a little like gas/exhausty when I park and get out of the car the last few days.

Assuming I do replace the part I'm a little confused on which O2 sensors will work. I saw the Denso 234-4623 mentioned, is this the proper replacement part? Is there a method to knowing which O2 sensors will work in a 2007 prius?

Finally, assuming the sensor is the issues, is there a problem if I continue driving the car locally? Besides that I presume there is some reduced gas mileage?

Thanks!