The court order will be honored not only in CA but throughout the country under Full Faith and Credit Clause of the Constitution.
Generally speaking, if you are paying child support and another child is born after the court order, your obligation is a little bit less, not much. Every superior court in CA has a self-help center which you can use their program, the Dissomaster to calculate child support. This is the program a court will use to determine child support and you can order it for $39.95 as well.