you can run a small FTP server to dump the save of the original and/or restore the sav (restoring is what your looking at here)
you will need the flashcard first to run the homebrew, the original game card, and a wireless router
there is a nice guide somewhere (google will find it for you)
i remember though that sometimes the homebrew can be really annoying and not detect your original gamecards straight off.
anyway, best of luck