Apply for the 1 year Extension of Stay based on marriage with a Thai National. The Officer will stamp your passport with Under consideration for 30 days. When the Officer gives the passport back, you directly apply for the Single Re-Entry Permit and inform the officer that you are outside the country for these 2 weeks. IF the Immigration Office is going to do a house visit, they will plan when you are back. Giving extra information to help out planning will be appriciated.
What do you describe as a work visa, is that the Non Immigrant B visa you bought from the Embassy before you made your way into Thailand and are still on the initial 90 days,
OR
Did you convert your tourist visa or visa exempt into a Non Immigrant B visa at Immigration and are still on the first 90 days
OR
Did you visit Immigration and got a new stamp with the text Extension of Stay is permitted up to xx.xx.xx
Totally different things with different rules, regulations and requirements and I hate to guess which one you have.
a Work visa that must be an Non Immigrant B visa in combination with a Work Permit. an Issued and used visa can not be changed to another reason.
a Study visa, that must be a Non Immigrant ED visa and if she left the course during the first 90 days after she entered the country, she can stay until her Admitted to Stay date stamped in her passport.
It all becomes a total different cans of worms is
a Work Visa is actually an Extension of Stay based on employment in combination with a work permit and
a Study visa is actually an Extension of Stay based on Education. But I hope the OP will explain what is inside his passport or just make a picture, delete the personal data en post the pictures if you do not know the name of your official stay inside Thailand.
If you have the Re-Entry permit you will be stamped in Thailand until 15 Aug, the same date you have now.
Thailand Immigration does not denied entry to people with less than 6 months validity on their passport, the passport must be valid for the period they get stamped in.
After you have the 1 year Extension of Stay stamped in your passport you can do with the money or the account what you like.
But be aware, over 10 months the 400.000 Thb must be in an account on your name or if shared accounts dubble the money for a new 1 year Extension of Stay.
TM30 has nothing to do with the way you enter Thailand.
TM30 is the number of a form used to register a foreigner residing at an address in Thailand.
But to answer the question, if you still have 15 days left on your stay, you can apply for the conversion into the Non Immigrant O visa based on being married with a Thai National. I would advise to ask for the requirements as soon as you go for the 30 day Extension of Stay, so you can prepare yourself.