Do you want to backup/restore the actual ringtone file, or just the contact setting for which ringtone to play?
I did something similar a while back, but I didnt use ringtones: http://www.b4x.com/forum/additional...o-contacts-sms-backup-library.html#post139763
It is possible to do via intents (i didnt try this) or with contacts provider, depending on whether you want to do just one contact or all of them.