What to do?
Turn it into a kind of 'bustle'.
Here is the original dress:
Use a seam ripper to carefully cut the seams and open up the back of the skirt all the way from bottom to top. This will become the front of the bustle!
Then cut it in half!
Here it is cut in half! The bottom half is the important half as I want to make a skirt, not a bra, so leave as much extra material as possible for the waistband of the skirt, cut as high towards the bust as you can!
Here is the finished bustle. You could also do it with a ruffly skirt!