Your question mentions the term "placement." It sounds like you have joint custody and that you have been designated the residential parent. If this is true, then you are entitled to receive child support payments from the mother of your child. If neither parent has been designated the residential parent, the court would look to the parent who the child resides with more than 50% of the time. That parent would be entitled to child support payments. If the child resides with both...
Assuming that the summons and complaint were personally served upon her, the time to answer is twenty calendar days.