Agyness Deyn needs a new boyfriend, or a new haircut, or both. A woman walked up to the British model at the Cinema Society party for “Brothers” Sunday at Abe & Arthur’s, asked if she was gay and propositioned her. When Deyn politely turned her down, the woman said, “If you ever change your mind . . .” Deyn, who only dates rockers, broke up with her last beau. Also at the bash: co-stars Tobey Maguire and Natalie Portman, plus Ang Lee, Bill Pullman, Amanda Peet, The Edge, Terrence Howard, Sam Shepard and Jessica Lange.