software update iPhone

No iTunes content is included with the iPhone's backup.

Although contacts are included with the backup, contacts are designed to be synced with a supported address book app on your computer, and there are a number of free email accounts that support syncing contacts over the air such as with an Apple iCloud account, a Yahoo account, Gmail account, and Hotmail account. Not a good idea to depend on an iPhone or any cell phone alone for contacts, which can be lost or stolen or damaged beyond repair.

All iTunes content that was on your iPhone should be in your iTunes library on your computer and included with your computer's backup along with all other important data. If not, check this link.

http://support.apple.com/kb/HT2519

You can try restoring your iPhone with iTunes from your iPhone's backup, but if there is a problem with your iPhone's backup in regards to this data and your contacts are not available on your computer or with any of the free email accounts that support syncing contacts over the air, your contacts are gone.