my husband is a green card holder. i came here as a tourist. got pregnant so wasnt able to go home. got an approval from nvc. what should we do?

Assuming you have not maintained lawful nonimmigrant (i.e. you stayed beyond your I-94), you will not be able to adjust your status based upon marriage to a resident. You would need to pursue an immigrant visa through consular processing, which means submitting the paperwork through the NVC. The problem with consular processing is that if you have been in the United States for more than 180 days without status, you would be subject to a bar of admission. This requires you to obtain a waiver based upon hardship to your husband if you were not admitted. You can read more about family immigration at http://myattorneyusa.com/family-immigration.