There is nothing in your link regarding support to the Ayatollah. The focus of the piece you've provided is that US support for the Afghan mujahideen began prior to the Soviet intervention, in an effort to destabilize what we perceived as a Soviet client state. Not exactly an earth shattering revelation, of the nature of your original statement.

Of course, the source that you provided is heavily slanted in an obvious direction. For more detail, and a more neutral look at the unfolding of those events, I highly recommend the GWU National Security Archive, the premier free-to-the public source for FOIA releases:

Afghanistan: The Making of US Policy 1973-1990
...Weeks after the Herat uprising and while President Carter was absorbed by the Iran hostage crisis, Brzezinski pushed a decision through the Special Coordination Committee (SCC) of the National Security Council (NSC) to be, as he put it, "more sympathetic to those Afghans who were determined to preserve their country’s independence."

Although deliberately vague as to what this meant, the evidence indicates that Brzezinski called for moderate covert support for Afghan dissident groups which had set up headquarters in Pakistan. Some, such as forces under the command of Rabbani and Hekmatyar, had been operating out of Pakistan without much outside aid for years. According to a former Pakistani military official who was interviewed in 1988, the U.S. Embassy in Islamabad had asked Pakistani military officials in April 1979 to recommend a rebel organization that would make the best use of U.S. aid. The following month, the Pakistani source claimed, he personally introduced a CIA official to Hekmatyar who, while more radically Islamic and anti-American than most Afghans, headed what the Pakistani government considered the most militant and organized rebel group, the Hizb-i Islami (Hekmatyar).

Freedom of Information Act requests for records describing these meetings have been denied. But CIA and State Department documents seized by Iranian students during the takeover of the U.S. Embassy in Tehran in November 1979, reveal that, starting in April 1979, eight months before the Soviet intervention and immediately following Brzezinski’s SCC decision, the United States had, in fact, begun quietly meeting rebel representatives. Although most of the cables and memoranda released to date show that U.S. officials politely turned down rebel requests for U.S. assistance, others reveal CIA support for anti-DRA demonstrations and close monitoring of Pakistani military aid for rebel parties based in Pakistan’s NWFP...