@Rj *****
Probably what you need is her blue book. It sounds like you are describing the chanote which is the land document. Bring what you think they might want. Both of you visit the immigration office. You either have what they want . . . or not. They will tell you what they want and then go get it.
Maybe someone from Korat will comment but in the end the immigration office is the definitive source for the answer to your question. You might as well find where the office is located and introduce yourself. While you are there ask what you need for your 1 year extension and how to do 90 day reports.