From your post, it would appear that you were convicted and given deferred adjudication probation. If so, that record cannot be expunged.
Generally speaking, the person's criminal charges must have been dismissed, or the person must have been found not guilty after a trial. Contrary to popular belief, a successfully served deferred adjudication probation cannot be expunged, except in the case of certain class C misdemeanor offenses. (An order of nondisclosure may be possible, however. See the section below.) Records subject to an expunction order may include those of the arresting agency, the Department of Public Safety, the court of prosecution, and the prosecutor's office. After the expunction order is entered, the person can deny the occurrence of the arrest and offense, as well as the existence of the expunction order.
Nondisclosure of Criminal Records Following Deferred Adjudication Probation
The Texas Legislature finally has passed a statute allowing someone who successfully completes a term of deferred adjudication probation to obtain an order of nondisclosure of criminal records pertaining to the arrest and offense. There are restrictions on eligibility, focusing on the person’s previous criminal history and conduct between the termination of supervision and the filing of the petition for nondisclosure. For many misdemeanor offenses, an eligible person may file the petition immediately upon discharge from the deferred adjudication supervision. For some misdemeanors, the person may not file the petition until 5 years after the discharge from supervision. For felonies, the person may not file until 10 years after the discharge from supervision. After the order of nondisclosure is entered, the person can deny the occurrence of the arrest and offense. Since this is a relatively new provision, it would be best to contact a local attorney to see what your eligibilty may be.
For a good explanation of the process and the limitations, go to:
http://www.sklippel.com/expuncti.htm
The process of expungement in Texas is covered by the Texas Code of Crim Proc at:
http://www.capitol.state.tx.us/statutes/cp/cp0005500.html#top