Ask your priest for guidance.
As has already been stated, you can approach the Sacrament of Confession if you meet the criteria for a good confession-- contrition, confession, firm ammendment of purpose, and satisfaction.
If you are sorry for marrying outside the church and are in the process of correcting the situation via convalidation then you have contrition. If you live as brother and sister until convalidation you have firm ammendment of purpose. If you do you penance, you have satisfaction.
Your priest will be the one to guide you on this matter. So, while the forum can give you general guidelines, only your priest can give you *specific *guidance in the confessional. If there is some element which you lack and the priest cannot give you absolution, he will tell you why and what must be done. He will also guide you on whether or not you should receive the Eucharist after your confession.