You should wait patiently for CPS to contact you, especially if you already have the child with you. The CPS referral would have been made for one of two reasons: either their is a claim that one or both of the parents are unfit or, the child is not in your custody. Presuming the child is in your custody, then you should just sit and wait. The investigation, here in So. Cal. normally takes about 60 days. If the mother's other child was taken and this child is with you, then you probably have little to be worried about. Good luck!
Your report should have been done months ago. Call the Probate Investigator on your case asap.
Check the probate notes on line to see if there are any updates you have missed.