KAROLINA Kurkova, the Czech supermodel often seen in the front row at Knicks games, is six months pregnant. The father is her fiancé, Archie Drury, a former Marine and Scientologist who made the documentary "Voices of Iraq." A rep at DNA Models said, "The couple have been together for a little over a year. This is the first child for both." Kurkova, 25, who's famous for her missing navel, plays Courtney A. Kreiger (a k a Cover Girl) in "G.I. Joe: The Rise of the Cobra," coming out Aug. 7. -PAGE SIX, NY Post