I'd probably lean toward just buying something--the Happy Tart in Del Ray is also a good source--or maybe bringing hummus with veggies. (I'm not GF, but I'm vegetarian, and I am always happy to see hummus at a potluck.)
A quinoa dish with dried fruit and nuts would also be good, I think, as would Tzimmes (basically sweet potatoes, carrots, and dried fruit baked together--gorgeous!). I love this recipe:
http://www.vegkitchen.com/recipes/carrot-and-sweet-potato-tzimmes/. Have fun!