Are you on PC? If so you can try the console command to resurrect her.
http://www.uesp.net/wiki/Skyrim:Console#resurrect
If you don't have a body to target in the console, you will need to type
prid 00019DD6first before using
enable and/or
resurrect 1, so the game knows what NPC you want to use them on.
I would suggest making a save before doing anything, just in case something goes wrong.
If you are not on PC, then I think you're out of luck unless you really do want to revert to an earlier save. Named NPCs don't respawn except for a couple notable glitches.