Hi Linzy,
There are quite a bit of changes so you would need to remove it completely before re-installing the new version. Just export anything you want to keep, preset, word/icon/sound set, then move the export folder to a folder outside of the Little Math.
Detail instructions are given by Shuki here:
http://forum.brillkids.com/little-math/new-build-release-little-math-beta-1-0-65