I´m in the process of getting the paperwork ready for extending my visa based on marriage. I have just received my letter of from my embassy, but am unsure whether I need to have it certifed at the Thai Ministry of Foreign Affairs? I remember as if I had to do it before, but cant find any "evidence" of doing it.

My permit to stay expire January 3rd, 2012.I assume I can apply for the extension now, right?

no you do not need anything from the MFA

That should not be required but there were at least a couple of offices in NE Thailand making that demand in the past. Advise your office for better advise.

Yes you should be able to do now.