A reasonable estimate for WiiU weekly sales during Q1 should be somewhere between 75 000 and 100 000 systems. In such a scenario we would see 900 000-1,2 million systems sold in Q1 and atleast an equal amount in Q2 and Q3. If so, all in all it's quite a remarkable achievement compared to last years sales during the same time period.
My estimate for 2014 is as followed;
Q1: 0.9-1.2 million
Q2: 0,9-1.2 million
Q3: 0,9-1.2 million
Q4: 2,7-3,6 million
This will put WiiU total sales at around 10,6-12,4 million systems at the end of this year. I believe that to be enough to fend off XboxOne, but PS4 will drive past WiiU sometime in Q3 and never look back.