How can I maximize my Non-O visa based on child support in Thailand?

What consulate did you get that visa from if you don't mind me asking?

You have a year-long, multi-entry Non-O visa based on supporting a child right?

On that visa you get stamped in for 90 days every time you enter the country for the validity of the visa (a year from the date it's issued).

When the 90 day stamp is running out you do a border-bounce <- go to the border, stamp out of thailand, stamp in&out of another country and then stamp back into thailand to get another 90 day stamp.

You do that for the whole year the visa is valid for making sure you're LAST bounce is just prior to the "enter before" date on the visa itself. That will take you to 15 months of stay (in 90 day increments) and then you apply for a 60 day "visit family" extension on that last entry for 1900baht and it takes you to 17 months of stay on a one year visa.