Kalla,
What you should do is two things. A. Ethier buy music on your phone. Or B. go to google and look for a website that downloads music for free. Download the song to itunes or windows media player (depending on your computer) and if your computer can't detect your phone (which could be a problem). You may need to download some software that allows your computer to detect your phone. If you have windows, that would be the best PC to connect your phone too.