Currently Being ModeratedMar 3, 2013 4:21 AM (in response to kaantje)
You can't sync books to DropBox from the iBooks Store and for what purpose do you want to sync books to iCloud? Your purchases are stored in the cloud for you, as long as the feature is available in the country in which you live. You don't have to sync anything.
You can see ant purchase are available for downloads again in your country here.iPad (3rd gen) Wi-Fi, iOS 6, 64GB WiFi