Hi,

My husband has filed a petition for getting me immigrated to he USA. He has filed I 130 form... Recently he has received a notice of action stating that the case has been transferred to USCIS for approval. Does anyone have an idea as to how long it will take for the approval to be granted and sending the case to NVC?

It should not be longer than 4 months, and then NVC has a window of 4 months to process your case. However, it could take longer depending on country you're from.