What happened to zukos mother?

on the tv series avatar the last air bender the season finale ends with Zuko becoming the fire-lord and him defeating azula to take the throne and aang defeats the fire-lord. at the end zuko asked his father about that happened to his mother but his father doesnt answer and the seriest end. what happened to zukos mother and the rest of the characters after zuko became the firelord and declared the war over?