The Qom plant, if current descriptions are accurate, cannot manufacture the basic feed-stock (uranium hexaflouride, or UF6) used in the centrifuge-based enrichment process. It is simply another plant in which the UF6 can be enriched.
Why is this distinction important? Because the IAEA has underscored, again and again, that it has a full accounting of Iran's nuclear material stockpile. There has been no diversion of nuclear material to the Qom plant (since it is under construction). The existence of the alleged enrichment plant at Qom in no way changes the nuclear material balance inside Iran today.
Simply put, Iran is no closer to producing a hypothetical nuclear weapon today than it was prior to Obama's announcement concerning the Qom facility.