O2 Sensor Problem

I have a 2004 Grand Prix Supercharge 6 cyl. and it has been running great for a while. My check engine light has been on for a while because of my procrastination and have finally come around to getting things changed out. I took the car to Autozone and had them check the computer. They indicated that the O2 Sensor was bad. And they gave me Bank 1 Sensor 1 error. It was time to change it out.