I don't think Iran is in as bad a position as you think. You will notice that over the past year or so, the number of centrifuges actually enriching uranium in Natanz hasn't changed, but the total number there has doubled. In other words, if the West were to actually apply new sanctions, Iran would retaliate buy doubling their enrichment. And if the west fails to provide 20% uranium, Iran can go ahead and produce it themselves. Fashioning it into the needed fuel plates may be beyond their expertise at the moment, but maybe in 18 months they could learn. Perhaps Brazil, following A'nejad's trip might even help with that. As for an attack, with Obama set to announce his Afghan surge, the U.S will be even more vulnerable to Iranian retaliation.
Australia to spend $64.9 billion on ships, submarines over 20 years (Reuters)
from the article: Medvedev to European Jewish Congress: Iran threat very real