You can always get the newest plugin here:
You will not get a notice of the new version in your admin plugin page because the plugin does not exist in the WP plugin repository. Eventually, we will build in notification so that you will get a message from the Store Options page.
I have never run an automatic update (I'm not comfortable giving out my FTP access details like that) so I don't know what went wrong for you. I would suggest you try this:
1. Deactivate the plugin
2. Download the newest version manually
3. Upload the plugin manually
4. Activate the plugin.
Then you will definitely have the newest version. If that doesn't work, I would guess there is a bug or something.
I hope that helps.