Sounds like they are just begging to be hit harder than just a few nuclear sites. Israel will have to take out Iranian leadership.
The easiest way for Israel to target the Iranian leadership is to let the Iranian people do it. This process can be aided by the proper application of multiple explosive divices to critical portions of the Iranian refinery complex, which would promptly shut down all of Iran's production of refined petroleum products. That's not particularly good for any economy, and I believe the Iranian one would collapse...but not before the army over there kills Ahwannajihad and his cronies.
Just a few dozen cluster bombs or cruise missiles, that's all. I'd do it for damned sure. Oh, and if I were the Israelis I'd also use a hundred different front companies to buy gasoline futures...you have to pay for the operation somehow.