Don't bother trying to get an extension. Immigration doesn't want to issue them and makes it impossible to get it. Instead you just leave every 6 months and return to get a new stamp. Immigration even recommends you to do that.
If they don't have the documents for an extension then they just leave the immigration office and nothing happens. Then they leave Thailand and return. Has nothing to do with the question that was asked.
you need to go to your immigration office and ask them for their handout of requirements for the 1-year extension based on marriage. That will tell you exactly what you need from the bank.
Are you asking about the 90-day non-O VISA, or are you asking about an EXTENSION?
If you are asking about the visa, are you asking about it from a Thai embassy outside of Thailand, or are you asking about it from an immigration office inside of Thailand?
The answers for all of these is different.
If you are actually asking about the immigration office, your VERY FIRST step is going to the immigration office and asking for their handout of requirements to either apply for a non-O visa based on marriage, or their handout for a 1-year extension based on marriage. This list will tell you exactly what you need for YOUR immigration office, since each immigration office has their own requirements.
There are some immigration offices that don't even allow you to convert to a non-O visa, so the immigration office is your first stop.