Married Son of U.S Citizen, 201(a) (3) INA
The next step is applying for your green card. However, you will have to wait until your priority date matches the cutoff date in the US State Department visa bulletin for your country of nationality. You have about a five year wait now unless you are Mexico or the Philippines which is about a twenty year wait. You may have other options and should consult with an immigration attorney.
The answer provided here is general in nature and does not take into account other factors that may need to be reviewed for a more precise answer. You should consult with an immigration attorney before taking any action. The answer here is not intended to create an attorney-client relationship.
Waiting until priority date becomes available by checking here: http://travel.state.gov/visa/bulletin/bulletin_1360.html.
Of course you should already have consulted with an attorney to see if you'd be eligible to adjust status (if you're in the us) or what to expect and how to prepare for consular processing (if you're abroad).
The information offered is general in nature and not meant to be relied upon as legal advice. Please consult an attorney prior to making legal decisions. Visit us at www.tunitskylaw.com. Contact us at 713.335.5505 or email at firstname.lastname@example.org. Veronica Tunitsky offers in-person, as well as telephone and email consultations.