Beyond the LCSW's class participation, which is a fine idea, how can your girl find a peer group she can feel comfortable with? I have counseled many kids in your daughter's situation and most all of them have found those good opportunities for friendships from belonging to groups outside the school. I would search your area for social, civic, athletic, religious, volunteer kid's groups. Talk with your daughter about these groups and see which ones appeal to her. My son found affinity groups in a pottery class and summer camp; my daughter found them in scouting and volunteer organizations.
When you join a new organization, be it a theater group or a 4-H group, you get a chance to "reinvent" yourself and leave the trappings of your school identity (the one others have created for you) behind. Good luck with your daughter's new beginnings. And don't be discouraged if the first experience isn't a dramatic success, keep trying.