The NVC should contact you within 4-6 weeks of the I-130 approval. They will first request the fee payment (2 payments totaling $492). You will then have to complete a DS Form 230 and Affidavit of Support in addition to providing them with original documents such as marriage certificate, birth certificates, taxes, etc... Once your record is complete (which greatly depends on how fast you collect the documents and forward them to the NVC), they will forward the file to Ciudad Juarez for an appointment. Appointment scheduling varies by the workload on the Consulate. However, the appointment should be scheduled within 45-90 days after the NVC document collection is complete. More NVC information can be found at the link provided herein.
If your husband is illegal in the U.S. and has been physically present here more than 1 year, he will likely need a waiver to reenter as his departure from the U.S. will trigger a 10 year bar to reentry. You should consult with a qualified immigration attorney before proceeding.