Received email from Immigration Bangkok informing me that I am able to extend my 90 day single entry Non-immigrant O visa for 60 days. Documents they require are marriage cert, wife's ID card, house papers (in my wife's name), completed form T7 with photo affixed, all of which I have.

My visa expires on Wednesday 10 September. If I travel to immigration on Monday 08 September and apply for extension, will I be too late?

Furthermore, do I have to take the wife with me?

Help and advice would be appreciated.

Anytime before it expires should be good - it will start at end of current stay. Don't believe the wife is a requirement for the 60 stay but if I were doing it I would try to have her with me. If not be sure ID card copy/home register is signed and dated.