The Church looks at any marriage outside of the Church between non-Catholics as valid. The problem comes when there are Catholics involved. As stated, it would seem that you, as a Catholic, are not free to marry this person and still remain in the grace of the Church and God.
As stated, you need to talk to your priest, who will help you understand.
Here is a very interesting link about a situation very close to yours:
geocities.com/seapadre_1999/noncatholicannulment.html
I do have one more question - are you sure you want to marry a non Catholic? There are untold problems facing you in the future, especially concerning your children. Please give this careful thought and prayer.
Mary