it looks like you need to do the application for the third extension short BEFORE September 30 deadline, and it will get you 3 more months, taking you to December 30. James Miller posted the picture that interpretes the rules regarding STV. It is all there, you just have to read it
you can do a 90 days report AT ANY IMMIGRATION OFFICE inside Thailand by visiting them personally . It is NOT limited to the branch of Immigration servicing the area where you reside
in case you are running out of time (which I think not as the bank issues a "rab roong thanakan" on the same day) you can still get the "family visit" 60 days of extension
you need to bring a bank letter of guarantee covering the recent two months plus must update your bank book on the day of application, by making one small withdrawal or transfer
James Miller i have non o visa now im looking for extension based on child and wife" . . which means he can get it based on either kid OR based on marriage with wife
4 - a 1-year extension based on being married to a Thai. Need proof of income minimum 40,000 THB per month, or a deposit of 400,000 THB on a Thai bank account in your sole name. The money must have sat in the account for two months prior to the day of appliction. Also need proof of legal marriage (rose bordered Thai marriage certificate) or legalized and translated foreign marriage certificate