You should clear up the registration and insurance immediately. Depending on your record with the court, the judge may let you off with a "continuance without a finding" or a dismissal upon payment of court costs. Of course, if the three year sentence is for motor vehicle related offenses, the court may not be so lenient. If your P.O. Goes to bat for you, s/he may recommend you just be restored to probation, although a criminal conviction is a technical violation. You can also ask the court to not hear the VOP until the current case is resolved.