There is! Talk to her at her house in Wacana Village ^^
Bring up the file of the old version, then click on the file inside labeled "www", inside you'll find another file labeled "save". Make a new save on the new version anywhere, then copy and paste the contents of the old version's "save" file into the new version's "save" file.
If you've already deleted the old World of Monsters file, you can probably restore it from your recycle bin, which should be on your desktop.