@Pe***
, you do not get a 30 day visa on arrival or a 30 day tourist visa you get into the country on a 30 day visa exempt entry stamp.
You need 15 days or more left on that stamp to apply for a 90 day Non-O inside the country. You cannot get a one week extension because there is no such thing, that is an extension denied 7 days to get out of thailand stamp for 1900baht and you can't apply for any visa once you get that stamp.
You will have a far easier time taking the marriage certificate, the thai i/d of your wife and her house book listing to the thai consulate in either Vientiane or Savannakhet Lao and getting a 90 day Non-O visa issued in a day.
You turn in your paperwork one morning and you pick up the passport with the visa in it the next afternoon. Neither of those consulates require proof of funds, OR any other documentation than what I mentioned.
Then once you come back on that 90 day visa you can apply for the yearly extension at your immigration office.