Hi Adam,
I recommend you to have 1.3x as 1.2 has some issues with shipping and 1.3x has alot more features than 1.2
If you have FTP and db connection details which are enough to do the upgrade, if you decided to do the upgrade make sure to keep a backup of everything (files and db) before doing any step, and to use the latest data tool version, anyway if you want i can help you doing that, just let me know.