replacement toilet flange issue. Please help if you can

Hi All.

I'm struggling with an issue I've not come across before. Removed laminate floor and found rot in flooring around area of toilet and near flange (PVC with what I believe was a cast iron ring. very rusted). In order to remove the rotted flooring, I carefully cut and pried up the ring and was going to use the Oatey 2-piece replacement ring.

The ring is a touch too big and wont properly surround the pvc lip. The OD of the pvc pipe is about 4 1/2 +/-" and the ID of the replacement flange is 5".

Any ideas/thoughts? The house was built in the 1980 and all in all quality materials were used in the building of the house.

Thanks in advance.

I normally leave the old ring in place to secure the flange, and if it's rusted out, use a repair ring more like this to hold the bolts.
http://www.pascospecialty.com/spotlight.php?pid=2&issue=33

If you are replacing wood though, you may want to replace the entire PVC flange, this time using a stainless steel outer ring.