We went from Canada for 55 days. While we were there, I found out that we could have applied for an extension in Canada before leaving Canada.
Since we were already in Thailand and decided not to go Into another country, we went to the immigration office and paid 1900 baht for a 30 day extension. It was an easy process and it was quickly done. Less than an hour. ( I guess it would depend on how busy the immigration office is that you go to)