When I was there in Dec they said "Winter 2013". Whether that means January-Feb 2013, or Dec 2013, I don't know. I'd hazard a guess at the former, but the CM didn't know either, just that they had been told to say "Winter 2013".
Both my guide and member services told me they have been told to quote Feb 2013 as the opening of phase 3 but that of course things can change. They both said that they also were told that if it changes at all it will likely be earlier than later. Obviously you can take that for what it's worth but since neither of them advised me that hey were guessing and told me that they were told to quote that timetable I feel confident about it.
Phase 2 (the Waianae Building) opened a few weeks ahead of schedule on November 15, 2011, so perhaps Phase 3 will open ahead of schedule as well.
Keep in mind that even when Phase 3 opens, it doesn't necessarily mean that DVC Members will have more villas available for booking with points. The number of villas that can be booked on any given Use Day is based on the percentage of the resort that has been declared for the DVC inventory. For example, AKV 100% of the resort is open, but only 74.96% of the AKV has been declared for the DVC inventory. Thus, one-fourth of AKV can't be booked using points.