Please make an appointment with your pastor to discuss the situation.
In general, yes, the marriages of non-Catholics are valid and therefore they are not free to marry someone else without either a decree of nullity (annulment) or in some cases what is called a dissolution of the bond.
If I understand you correctly, you married a divorced woman outside the Catholic Church. Your marriage is not currently valid, and in order for it to become valid, yes, her prior marriage would have to be found null or dissolved via Pauline or Petrine Privilege. Then your marriage would have to be convalidated.
GO SEE YOUR PRIEST.