Your husband can petition for his parents once he is a US citizen. Until then, they can try for tourist visas. They may also apply for investment based visas. Costs for any of the above vary by attorney and visa.
You need to prove Good Moral character for the requisite three years as the spouse of US citizen. If you have had no problems since then, you should be ok. Make sure you apply after three years have passed from your conviction and be sure to disclose this whether or not you have it "expunged" from your record. In San Francisco the interview should be scheduled within 2 1/2 to 3 months of the date you apply.