Well, using Nintendo numbers (The real sale figures) which means it is already at 1.8m units sold, I would say it will reach 2.6-2.7m in 2013. Using Vgchartz figures, I'd say 2.m-2.1m. So I guess 2.65m or 2.05m.
Predictions for LT console sales:
PS4: 120M
XB1: 70M
WiiU: 14M
3DS: 60M
Vita: 13M