You have to be living with your wife and your wife have to go with you to immigration. They might also want some witnesses to confirm you live to gether and the marriage is genuine. Immigration will not convert to a non-immigrant via as you already have one, but give an extension of stay based on marriage with
If you de not meet the requirements, you have to leave the country and apply for a non-O at a Thai consulate, poosibly a multiple non-O.