Macbook broken, freezing up. How should I get my files?

I was told by my friend to back up all my files just in case this repeated freezing whenever I open Firefox or another program is fatal to my computer. How should I get all my iTunes songs and pictures? I don't have any blank CDs and my 2,000 songs and 3,000 pictures definitely would not fit on a CD. Anyone know another way? I don't have an external hard drive or anything either...