"Multiple sources" in Yonhap's report said Kim had Jang's two brothers' sons, daughters and grandchildren; Jang's sister; her husband (who was North Korea's ambassador to Cuba); Jang's nephew (North Korea's ambassador to Malaysia) Jang Yong-chol; and Jang Yong-chol's two sons killed. Jang Yong-chol's wife and others who were not related to Jang Song-thaek were spared but sent to "remote villages" with whatever family they had left.
The report couldn't specify when the executions took place except that it was after Jang Song-thaek's. It's worth noting that recent stories about North Korea and executions were later proven to be false, so take this one with a grain of salt (as you should probably take all North Korea news).
As for Jang Song-thaek's wife, Kim Jong-un's aunt Kim Kyong-hui, she is believed to have survived the purge but hasn't been seen in public since September 10 and is either dead from a heart attack or suicide or in a coma after brain surgery, depending on who you read.
When Kim Jong-un isn't busy ordering to have one family annihilated, he's been proposing that family reunions between North and South Koreans resume. Tonight, South Korea asked North Korea if family reunions between the two countries could take place between February 17 and 22.