Tds on purchase of property from nri

Hi,

My query is about purchase of a property from NRI in India. 

The Seller is an NRI and not providing the certificate from the ITO regarding the capital gains on the property. Please help me with the following queries.

1. In such cases, how much TDS should be deducted. ?

2. From when the period of holding is calculated. Is it calculated from the date when all the payment has been by seller to the builder, or from the date seller got the possession or from the date when the flat is registered in seller's name.

3. Also is Long term gain and short term gain applicable on this as i believe TDS is to be deducted on the sale value.

Please suggest on the same.

Thanks 

Rahul