Tresspass and holding of security deposit by Landlord

This query is regarding the dispute between me and the landlady. I have rented a house in Bangalore and 10 months rent was given as a security deposit which need to be returned at the time of vacating the premises.I had informed the landlady on Oct 2nd,2015 that we will be vacating the premises with 2 months notice(as per the agreement). However on Nov 1st landlady has informed that she cannot return the security deposit due to lack of funds which I have not accepted. Landlady has disputed mentioning that notice should be given in written and it will be considered from the date letter is given, further I have handed over a written notice which she was not ready to acknowledge and did not sign it. I had sent a registered post on Nov3rd which was also not claimed by her and it was returned mentioning(unclaimed after 3 attempts). On nov 5th landladys daugther has posted a notice on our door mentioning that we are creating nuisance and need to vacate the house within 2 months(last date was mentioned as Dec 12th 2015), based on this I had vacated the premises on Dec 19th, and requested the landlady to inspect the property which she has denied mentioning that i have not given any notice.When the security deposit was not refunded I had locked the door with another lock I had lodged a police complain on Dec30th mentioning cheating by landlord and i have got the acknowledgement for the same.On Jan 10th when i visited the house i found that the lock was broken and landlady has taken the possession of the house.Now the landlady is claiming that security deposit will be handed over after 2 months(deducting 2 months rent) citing there is no written notice given before vacating the premises. My queries are 1. Do i need to log a fresh police complaint for trespassing the property, Since she is deducting the rent for 2 months I suppose still i will be considered as a tenant. 2.If i file a civil case usually whats the duration of such cases 3.Police has just given the acknowledgement, is an FIR required for this case.