Under a recent change in policy, where the U.S. citizen spouse dies before the second anniversary of marriage, if the surviving spouse has not remarried and was not legally separated from the citizen spouse at the time of the citizen’s death and is residing in the United States, the suriving spouse and the surviving spouse’s children are now entitled to humanitarian relief in their pursuit for Permanent Residence.
Although I can't promise that policy won't change back to what it used to be, you say you're already past the two year mark.

