If I fire my attorney in a civil case and being the Plaintiff , can I ask the judge to extend to aquire new?

The extension is called a ';continuance.'; You can ask and the court may or may not grant it. If the judge thinks you are doing it just for delay, or if there have been other continuances, or if you wait until the last minute and the other side has witnesses who have been inconvenienced, then the judge will probably deny the continuance. If you do it well ahead of time, and give some good reason for your decision, and it does not hurt the other side, then the judge will probably grant it.