Have OST/case next week. what should i expect. disagree with temp. custody/visitation order.

Respectfully, the facts as relayed are very confused.  Apparently, there are multiple relationships overlapping here among you, the father, and his wife.  I can't tell what court orders have been entered, by which courts, or why, all of which is extremely important to determining what to do, and how to do it.  I can't tell how long of time has gone by since the child left, why the child left, whether the child left with your consent or with a court order approving it, who has filed or is trying to file what, where, or what, exactly, CPS is doing, or when. With that many unknowns, it is impossible to give any meaningful guidance beyond those for preparation.  First, assemble all court orders, notices from CPS, correspondence among any of the adults indicating any agreements as to what is being done with the kids, etc.  next, create a time-line, as the facts are confused.  A guide to how to do a timeline is posted at http://willicklawgroup.com/consultation-policies/. You are almost certainly going to have to go over all of that paperwork, timeline, and your questions, with competent family law specialist counsel.  You don't say when your hearing is, but you should try to have that consultation as far in advance of the court date as possible.