It sounds like your conviction will qualify under the "petty offense exception" assuming it was a misdemeanor. If that is the case, it shouldn't affect the renewal of your green card. In my experience however, the Phoenix naturalization office will deny applicants with ANY criminal history during the good moral character period. This would mean that you should wait until 3 years from the date of your conviction (if you're marrying a USC) to apply for naturalization so that conviction will fall outside the Good Moral Character period.
As long as this is your only offense you should be fine under the petty theft exception although it does reflect on oyur moral turpitude. Hire an attorney to assist oyu with the application