Dear Concerned,
Your kids being older than 7 years you automatically become the natural guardian of your children and since your children are staying with you , your wife cannot forcefully take them with her. As, this marriage seems not to be working you should pronounce talaq restricting your wife to forcefully to come to your house.
Custody of your daughter will be subject to the conditions as per personal law(Shia or Sunni) which may also be based on situational analysis by the Court as in your case your wife is not willingly taking the custody, hence, chances of you getting the custody of your daughter are bright.
Best o Luck-Stay Blessed.