Unfortunately, they'll just have to make do for the moment; getting aircraft from the Russians might have to be an option, although if there are sanctions, air routes might be one of the targets, with Iran Air flights to Europe being hit.
However, since many flights between Europe and India and the M/E fly over Iran, they would need to be careful.
Ultimately, the nuclear deadlock will have to be broken by Israel, although in some ways that's likely only to play into the hands of the mullahs and the hardliners like Ahmadinejad.
The sad thing for Iran is that the end to this crisis will have to come about as a result of their actions and that doesn't seem likely; there is a huge young population in Iran and they've been largely turned off politics by the recent elections. However, with fundamentalism obstructing many of the new "freedoms" (or tolerated transgressions), they can only be pushed so far.
An isolated Iran will see poverty grow and unrest with it; one can only repress so far or chant so loudly; sooner or later, reality has to dawn. Iran Air will only recover to its (very considerable potential) when the current leadership has been flushed away. That can only happen with bloodshed and that is probably not imminent, so really, it will be quite some years before IR
gets anywhere. It may well have to consider Ilyushins and Tupolevs in the meantime.