one strap prom dresses

I'm searching for a wedding dress sized 18-20. I would prefer straps, but strapless will be fine just as well. I need one before august 19. But I would like to try to see if I can find one before this weekend. Please nothing too pricey or too overdone. My very last resort would be my prom dress from four years ago, and I'd rather not wear a florescent pink dress to my wedding. Anything would be helpful. Please send pictures of front and back, along with tag. one strap prom dresses