no you cannot extend any visa at your embassy, you arrived on a 30 day visa exempt stamp not a visa at all,but you can extend your stay for another 30 days at your local immigration office for 1,900 baht each, good luck
You don’t have a 30 day visa at all, you have a 30 visa exempt stamp, which you both can extend once only for another 30 days at your local immigration office for 1,900 baht each.