Declaration of interest income for senior citizen in itr

Please go through the iinformation below for answering my tax query:

1. I had transferred 20 lacs to my mother's account in FY 2011-12 and created a Fixed deposit in my mother s name.( to save TDS ) My mother is senior citizen and submitted form 15H. No TDS was deducted by bank. Interest income for FY2011-12 is Rs 40000 while Interest income for FY2012-13 is Rs 160000. She is a house wife and has not fied any tax return before.

2. In FY 2012-13 , my mother sold a residential property for Rs.11 lacs on which LTCG is applicable.

3. She wants to use the proceeds form this sale for buying another  house and wants to claim exemption on LTCG . Sale proceeds have been kept in Capital gain account with a nationalised bank.

My Questions:

1. In order to claim exemption on LTCG , she will need to file an IT return for FY 2012-13 .

•    Should she declare her interest income for FY 2012-13 ( Rs. 160000) in this return ? How closely IT dept monitor 15H declarations ?
• If interest income for FY 2012-13 has to be declared in ITR -  than since she also had interest income of Rs 40000 in FY 2011-12 , should she file ITR for FY 2011-12 also ? What is the last date by which this ITR can be filed.

2.   What declarations/documents do I need to make for the amount I transferred to my mother - just to be on safer side with IT dept.

3.   DO I need to have gift certificate declaration for the amount I transferred to my mother - just to be on safer side. What is the format for such a gift certificate and how I can obtain it.