Halloween // Costume ideas needed!!

My husband and I are invited to a Halloween party next month. The dress code is Gothic Victorian (think Tim Burton's Sweeney Todd or Corpse Bride)

I don't really have anything in my wardrobe currently that I could use for a costume. I've also recently lost about 30lbs so I thought it might be fun to be a little bit sexy. I'm on a pretty tight budget so whatever I do needs to be under $100 total. I was thinking of getting a corset and then making a layered skirt somehow out of black lace curtains or something, but then I get stuck what to do for the rest.

I'm a plus size girlie, sitting at about size 18/20 at the moment so that also limits my options. As of all that weren't enough, I'm not really a sewer. I have access to my mom's sewing machine if I need it but I lack skills.

Any ideas to help point me in a clearer direction would be GREATLY APPRECIATED. As you can probably tell, I'm lost.