Possible punishments?
If this is your first offense for being a minor in possession of alcohol, which is a Class 1 misdemeanor, you may receive probation and a suspended license, with proceedings deferred until the terms of probation are met. If you meet the terms of the probation (community service, substance abuse assessment and treatment, and/or education, etc), there can be a dismissal with no adjudication. There would be no record of your minor in possession charge, although law enforcement officials or the courts could still access it, should you violate this or any other law in the future. A Class 1 misdemeanor has a mandatory minimum fine of $500 and/or a mandatory minimum 50 hours of community service as a condition of probation (this fine and the community service hours may be just for adults or emancipated minors however - for minors it may be less).
For the retail theft charge, that would be petit larceny, I believe, and a Class 1 misdemeanor, with fines and jail time up to the discretion of the court - jail time could be up to 12 months and/or a fine could be up to $2500. The merchant could potentially bring a civil action against you, recovering two times the amount on the unpaid retail value of the merchandise, plus attorney fees and costs up to $150, or liquidated damages up to $350 if the merchandise was recovered and is still saleable.
Although the above information was taken from the virginia.gov website, I may have inadvertently transcribed or interpreted something wrong - so wait for other posters to correct any misinformation here.
Also, going to AA and starting community service would not be a bad idea, however you will probably be required to do both (or at least something similar to AA) anyway, as a condition of probation. As for the $600 covering the cost of an attorney, around here it would purchase the services of a decent attorney for 3 hours only.