If the OP is on an extention of stay from his ED visa he doesnt need to leave the Country, he can change the reason for his extention to marriage providing he's seasoned the 400k for 2 months.
You should've got the 60 days first. If you didnt tell Immigration you have Thai dependants they'll only give you 30 days. You may be able to get the other 30 days by going back to the Immigration office.