Wife deserted us 6 months back: Not giving divorce

Hi My wife deserted me & my daughter 7 months back. She left the house all of a sudden and without any reason . She is asking for 25 lacs to sign the divorce papers and threatening me that she won't give the divorce unless i pay her this amount & she will ruin my entire life. I am sorry i can't afford to pay any alimony . I want to move on with my life. But not sure, how ? Please answer my below questions :- 1)Can i file the divorce based on the desertion grounds ? 2) How long will it take to get the divorce, given the fact that my wife is not cooperating and is not willing to give me the divorce ? She just wants to stay separate so its ruining my life. 3) My daughter is 5 years old. My parents too care of her since her birth. And my daughter wants to stay with my parents only. Can my wife still get my daughter's custody? I want to claim my child's custody based on guardian law.