Hi,
from our question, following is the understanding:
1. You have finalise the flat with owner.
2. Yoy have paid the token amount for flat to owner.
3. Owner is wiiling to make make registration ( sale deed in May 2013)
So in this case you can make agreement to sell at this point which contains the detail of sale property & schdule foe payment.
In pune you can contact Mr. Sunil Gokhale : 9823164284