Ahmadinejad is a figurehead. The real power is the Assembly of Experts and Supreme leader Ayatollah Seyyed Ali Khameini who replaced Khomeini. Since 1979 there has been only two Supreme Leaders. Ahmadinejad is just stirring the pot. It probably helps raise the price of oil, which is now going down.
This 2006 article says you are wrong and he has even more power two years later:
Iran Chief Eclipses Power of Clerics
TEHRAN, May 27 — President Mahmoud Ahmadinejad is trying to consolidate power in the office of the presidency in a way never before seen in the 27-year history of the Islamic Republic, apparently with the tacit approval of Iran's supreme leader, according to government officials and political analysts here.
That rare unity of elected and religious leadership at the highest levels offers the United States an opportunity to talk to a government, however combative, that has often spoken with multiple voices. But if Washington, which severed relations with Iran after the 1979 revolution, opened such a dialogue, it could lift the prestige of the Iranian president, who has pushed toward confrontation with the West.
Political analysts and people close to the government here say Mr. Ahmadinejad and his allies are trying to buttress a system of conservative clerical rule that has lost credibility with the public. Their strategy hinges on trying to win concessions from the West on Iran's nuclear program and opening direct, high-level talks with the United States, while easing social restrictions, cracking down on political dissent and building a new political class from outside the clergy.
-SNIP_
Just like so many other things the NYT reports, they are full of it. The Supreme Leader and the Revolutionary Guard control the country.