I think there's a couple of ways you can go. The majority of the states don't recognize common law marriage...Texas does. You can get a form from your county clerk, fill it out and file it. They will then record it and you will be recognized as married.
Another thing you can do is petition the court to recognize the marriage that already took place. I have no idea whether it would be approved but my guess is that it would....simply a guess.
In any case, I'd go back to the courthouse and speak to someone else who's willing and able to give you more information.

