Hi Jagadeesh,
Answer to your first question yes u can take interest & Principal amount benefit by showing the interest amount under Income from House property and the same will get adjusted against your income from salary head and for this you can use ITR 1.
Further in reply to ur second question u can claim HRA benfit under section 80 GG only if the following condition are fulfill:-
Section 80GG - In case you are not in receipt of HRA and Rent free accommodation (RFA) and you/your spouse/children do not own any residential property either at the place of your work or residence, or if your spouse/children own a residential property at any other place (but not the assessee), then you can claim deduction for the rent paid as per sec 80GG under Income Tax Act, 1961. The same is explained below:
Deduction (under sec 80GG) allowed is least of the 3 options below:
a) Rs 2000 per month;
b) Excess of rent paid over 10% of Adjusted total income;
c) 25% of Adjusted total income where, Adjusted total income is-Gross total income - i) LTCG (if already included in Gross Total income) - ii) Aggregate (sum) of Deductions under Chapter VI A (excluding deduction under sec 80GG).
Note:
1) You need to be paying rent, and for your own accommodation, not for your parents' accommodation.
2) You need to declare that you are paying the rent. This has to be done by filling out and filing from 10-BA.
3) The house is to be situated within specified municipal areas. However, all major cities are a part of the specified municipal areas.
Hope this solves your doubt