The G2 is equipped with a microSD memory card reader. If your laptop or personal computer can also read that kind of card (Most notebooks are so-equipped), you should be able to transfer music files
The NUU Mobile G2 is an Android smartphone and the Android market offers a bunch of free ringtone apps such as MP3 Ringtone Maker, Zedge and more.
Learn more about making your own free ringtones
Here are links to some of the all free ringtones (compatible with your NUU Mobile G2) we offer:
Free 'Unclassified' Ringtones Free Tropical Ringtones Free Ringtones-a-gogo Free Techno Ringtones Hear All Our Free Polyphonic Ringtones