Iddat for a Muslim woman who’s husband was a Kafir is one month.
Iddat for a Muslim woman who was wife of Muslim husband is 3 months (if she moved to his house)
There is NO Iddat for a Muslim woman who was wife of Muslim husband but she did not move to his house.
Source:The ‘iddah of a woman divorced by talaaq](“http://learnislam.freeforums.org/the-iddah-of-a-woman-divorced-by-talaaq-t67.html#p154”)