You don't have to wait for the card. You can send a copy of the visa and stamp in your passport. You must send the application when you're in the country, and then go to the biometrics appointment a few weeks later. You can leave in-between the time CIS receives the application, and your appointment, but someone must check the mail for you. They will send the approved permit to the embassy or consulate where you live abroad. You can stay out of the country for around 2 years. Apply using form I-131.