The Catholic Church recognizes and respects marriages of non-Catholics as valid. A person validly married to Person A cannot marry Person B. Divorce does not end a valid marriage, as Jesus taught us. Therefore, civil divorce does not free someone to marry another.
You can petition the Catholic Church to evaluate the facts surrounding your marriage to determine whether or not a valid marriage was entered into from the beginning. If so, then you are not free to marry anyone else until the death of your valid spouse. If not, then a decree of nullity would be issued and you are free to contract a marriage with another.
So, your first step is to make an appointment with a Catholic pastor to discuss all the details of your marriage, and he will guide you from there.
There are many factors such as baptismal status of both parties, whether or not either party had attempted marriage in the past, whether or not the other party was a Catholic, etc.
Because there are many variables that could impact the situation, we can only give general advice here. Bottom line, you must be declared free to marry before you can proceed to marry anyone else. If/Once you are declared free to marry, then the marriage preparation process can begin with your intended. There will be marriage prep and paperwork to be done.
So, make an appointment with her pastor and start from there.