o2 sensor 97, need help immediatly

My o2 sensor went out on my 97, 4.0. It is behind the cat. I pulled it, went to the parts store, and the sold me a Bosch 13272 (i think). Anyway, it won't fit. There is a metal sleeve around the sensor that won't let it fit into the cat. Every parts store lists the same part. Does anybody know what other sensor I can use, with out going to the dealer? I can't be the only person to have run into this problem. I'd like to not have to drill out the hole in the cat. Thanks for the help

You can see the ring that is preventing me from getting the new sensor in. it doesn't move, so I am going to drill it out unless anybody has a better idea. thanks

now I drilled it out, got it in, and ran it. Now I get an error about my voltage being wrong, error #21. Any ideas?

Incase anybody is actually reading this..........
now I've replaced both sensors, it is running better, still not the best mileage, but that could just be where I've been driving, but the error codes haven't cleared yet. Why are the codes still causing my check engine light to be on?

You need to clear the codes. If you have the decoder manul or shop manual it should give you the correct process. Then you'll have the current error codes.
Craig