Try walking toward the light while she has you up in the air. Sometimes landing on the base of her statue rather than the ground is enough to save you from death. Also, try dropping some stuff before taking the sword to lighten the load you're carrying.
If you have a save from before you got stuck in the final room you can create a super powerful fortify health suit and survive the fall that way.
I have detailed my method of that when I encountered this bughttp://www.gamesas.com/topic/1462042-the-break-of-dawn-game-breaking-glitch/.
I suspect that in my case the bug was caused by me taking the quest late in the game, at level 70 or so, and by that time the game had likely amassed a lot of variables resulting in script lag.
The script to teleport would try to activate, as I could see by the edges of my screen going white, but it did so far too late resulting in my unavoidable death. None of the tricks mentioned about positioning yourself worked for me, I did manage to survive once I made a suit that could absorb 32k+ fall damage. This is with the heavy armour perk that reduces fall damage so you'd possibly need more than 32k.