1. Go to the Courthouse and pick up a copy of your "minute order" from the clerk's office - a summary of what has happened in your case over the years. Confirm that your probationary period is over. It should be since your conviction was in '06. However, since there may have been probation violations that you were/were not aware of, the probationary period could have been tolled for certain periods of time.
2. Assuming that you are no longer on probation for this offense or any other offense, it is a matter of completing and filing the Petition. Often, information from the "minute order" that you can pick up from the Clerk's office will obtain the information you need to complete the Petition.
3. If you still have questions as to how to complete the Petition paperwork, you should hire an attorney. You should be able to find an attorney who will assist you for a reasonable fee.
4. While the conviction you suffered is relatively minor, you may want to hire an attorney to assist you in ensuring the Petition has a greater likelihood of being successful, considering the Judge who reads the Petition will see that there was some difficulty fulfilling the requirements of the Court.