if restrictions are still running on, you must should try to go at the local national oil company office, as i did it in orumiye, on last august. they'll probably shake you, from an office to another in a couple of hours, but at the least, you'll have a card (or two it depend by the need) in your hand.
i had it two, payng 40 eu. for both. then, with it go to the gas station, put the card onto the pump cardslide, refueling, and pay for each litre brought,
1000 Rials. beware! you can have 24 lt./day only, with one card. don't get wrong! or otherwise, if you have a lot of time to spend in Persia, reach the gas station, and ask to the locals to purchase it by them. last chance, as a dutch guy did, when i met him in esfahan, wait! someone will approaching you, asking "may you need a help? ", they'll give it to you for free...
KHODà HAFèZ ( see you! )