The court on motion of a defendant may grant a new trial to that defendant if required in the interest of justice. If trial was by the court without a jury the court on motion of a defendant for a new trial may vacate the judgment if entered, take additional testimony and direct the entry of a new judgment. A motion for a new trial based on the ground of newly discovered evidence may be made only before or within two years after final judgment, but if an appeal is pending the court may grant the motion only on remand of the case. A motion for a new trial based on any other grounds shall be made within 7 days after verdict or finding of guilty or within such further time as the court may fix during the 7-day period.