The easiest way to insure you don't have to re-enter ingredients if you re-install the software is to back up all the *.DAT files in the ProMash directory. They are small and will fit onto just about any media type (floppy, CD, memory sticks, etc). Then you can just copy the DAT files back in after a re-install. No need to do anything else if you are looking to simply save your data.
That said yes we are addressing the import/export needs in the next release so that new data can be shared easier from user to user.