Assuming she was charged with misdemeanor obstruction, the maximum punishment is 12 months in jail and a $1000. If the charge is a felony, she faces up to five years in prison. For a first time offender, there are ways to resolve her case short of a criminal conviction. You should consult with an attorney as soon as possible.
The warrant remains in place until resolved. Since the underlying charge is a misdemeanor, it's less likely you'll be arrested if the warrant is discovered, but you need to address it at some point. Why not call an attorney and get some assistance?
I'm guessing the case was dismissed at a probable cause hearing, which would not preclude a subsequent filing of a formal charge. Contact an attorney right away to discuss your god son's situation in detail.
Rather than ask this question on an open forum site, why don't you call several attorneys directly and meet with them for initial consultations? That way, you can get a fee quote based on the unique circumstances of your case.
It sounds like you received notice for a warrant application hearing, where a judge will hear evidence and decide if you should be charged with a crime. You will need an attorney to assist you, and I suggest you speak with one before doing anything else.