@Kween *********************
There are 3 things you can do to stay longer
1 - GO to the immigration office that serves the area where you stay and get a 30 day extension on the current stamp you have for 1900baht.
2 - GO to a border, stamp out of thailand, stamp in&out of another country and then stamp back in to thailand to get a NEW 30 day visa exempt entry stamp
3 - GO to a thai consulate in another country and BUY a single entry tourist visa so when you come back in to thailand you get stamped in for 60 days.