At the suggestion of k2wilde, I booked Motel One Wien-Staatsoper, 2 rooms for 270 Euros per night with rights of cancellation. After that, I received a reply from Pension Suzanne for 200 euros per night for a quad room, breakfast 10 Euros each extra. Then I looked at Booking.Com as suggested here and found what appear to be nice apartments at 200 per night or less.
With several rooms available, I went back to book the flights only to find that they went up 40% from yesterday!! I guess I will wait until mid week to book the flight and then go back to booking.com or to Pension Suzanne for accommodations.
Somehow, with your GREAT help, I will work this out and enjoy Vienna at Christmas time.