Audrey brought her bunny costume with her to change into after setting up. She had a fantastic birthday cake along with a handful of different kinds of muffins, a dozen or so of each. After setting up the food and dropping a couple bottles of rather fruity wine on the refreshment table, she hopped into the bathroom and changed into her costume, then came back out, feeling a little sheepish. Her costume was cute and slightly flirty, but not over the top. Perfect.
Audrey didn't know the Weasleys all that well, but she liked them very much. She knew some of the other Gryffindors that would be at the party (she assumed Alicia and Angelina would be there--and they were all in the same year at Hogwarts) but she sort of felt like the odd one out in the room.