Apple has made this their industry standard and requires users to import third party ringtones through iTunes, unfortunately you have to use a computer when importing ringtones to iTunes and your device.
To set the saved ringtones you have to sync your device with the newest version of iTunes. Please open up the APP MENU and click on RINGTONE GUIDE for a step by step guideline. As soon as you complete the steps in the Ringtone Guide you will be able to access the Ringtones on your device.
To set a Ringtone go to SETTINGS > SOUNDS > RINGTONES > Select the Ringtone of your choice