K-1 visas allow U.S. citizens to bring their foreign national fiancé(e) to the U.S. in order to marry. If you are already married, then you are no longer eligible to apply for the K-1 visa. You should apply for a K-3 visa to bring your spouse to the U.S. The K-3 visa process is similar to the process used for K-1 visas, but not exactly the same.
Here is a link to more information about the visas which are available. http://www.battanlaw.com/Practice-Areas/Fiance-and-Spouse-Visas-K1-and-K3-Visas/
Tip: Because the process is highly complex, it is strongly recommended that you hire an immigration lawyer to help you prepare and file your visa petition. The attorney will also help you follow the process through the system, apply for your visa if you are approved, and guide you in your new status in the U.S.
