You can use the Liztic desktop app, available for Mac and PC, to manage the content on your iOS device. Actually, when you have a library on your Mac or PC, you can also "pull" the music from your desktop to your iOS device.
I invite you to download and try out Liztic for free with a Basic account, the apps are available on: http://www.liztic.com
Please let us know if we can help further:
[email protected]
Thanks!