'm in the middle of a divorce and the judge is totally bias against me can I get a change of venue or drop the divorce

Your lawyer should have advised you about moving/new county after a case has been pending. I have seen it accomplished in rare instances.

Yes. If you both have moved on with your lives, the process shouldn't be too complex.

How do I go about getting full custody of my children? How long is this process?

Consult a family law attorney to determine custody and visitation. You will also want to consider setting child support at the same time.