Hra exemption - urgent query

Hi,

I want to claim HRA exemption for the rent paid by my father from my employer.

1. Rent agreement is in the name of my father till 15-Jan-2015 only which will be renewed after that. Will I be given exemption for all months or only 10 months?

2. Landloard will issue rent receipts in the name of my father only. Will I get exemption of HRA if I give declaration to my employer that my father not claiming HRA exemption and have taken rent from me to pay our landlord?

3. Can a consolidated rent receip/declaration from fathert for full F.Y. be given or should it be monthly basis?

Pls give circular /notification from CBDT if any to support your answer.

Thanks.