According to your case you can can take following action;
If your wife is demanding large amount, you get that demand on paper by writting a letter to her asking for settlement as per high court order without referring any amount. If she replies, you can use her reply/demand against her, but if not replied you can try it out by recording her statement by a electronic device like your cellphone or other and keep it, which can be used against her.
If your wife is living with other person you can file a complaint under adultery against that other person for having s*xual relationship with your wife provided you can prove it and you are not divorced.
After doing above things you can file an application in your writ petition before high court stating all the facts of her demand and also facts of her realtionships with other person and pray for necessary direction and seek interference of judge in arriving settlement amount if court is inclined to settle/quash the complaint.
However, the offence u/s 498a is not compoundable and non bailabale. Hence, if court could not settle it you have to contest it before trail court.
If divorce petition filed and pending, you can contest it on the groung of adultary.