We will be adding other import options in future.
You can transfer your existing notes either through iTunes, or by downloading them from a site like dropbox. To do this, you need to make a study archive, which can include CSV files, but also images and audio. (That is why we use this format rather than straight CSV.)
It is quite easy to make one of these archives. You just export the text as two columns of CSV, then make a few directories and zip it all up.
Full directions can be found here: http://www.mentalcaseapp.com/studyarch Please let me know if I can be of any more help.