Hm, its kinda strange that so many airlines are still moving to Vnukovo. Lufthansa also transferred some flights from Domodedovo to Vnukovo (and is said to have heavy problems there). Not only that Vnukovo is a small provincial (but international) airport, but Putin himself announced about a year ago that the city owned Vnukovo airport will be merged with the government owned Sheremetyevo and closed soon. Domodedovo is privately held, but the government tries to get their hands on it, yet unsuccessfully though.
And yes, you counted right. We have 3 international airports around Moscow. 2 in the South / West (Vnukovo and Domodedovo) and one in the North West (Sheremetyevo).