Wife given written statement saying i filed false 498a

There is no max time limit to file counter cases. It is your wish you can file whenever you wanted depending on the case details. But it is recommended by many lawyers not file any counter case against until with proper evidences. 

If you have the written statement of her saying in PS , with a stamp on it of her own handwriting i would not think of time to file a case on her. I would definitely file  a divorce case on grounds of cruelty, defamation suit. 

Has the case filed against you finalised and a copy of order received stating therein that the complainant has filed a false case or it is dismissed for (XYZ so and so reason) or do you have certified copy of her statement stating therein that she hasd filed a false case, then you may move otherwise it is definite to back-fire upon you, mind it.

There is no such thing called a counter case for 498A;  if it is proved that it was a false complaint based on which Police initiated the said case, you have option to file a libel case against the police for damages caused due to improper investigation and resultant false case or else go for a divorce against your wife on the grounds of cruelty for which this false case is a strong evidence

Thank you all for your valuable answers.

If I have all the evidences to prove that it is False 498A, how many months/years it will take for the court to give the final verdict?

And approximately how much money I have to spend from my pocket from initial stage of this case until final verdict?