Rocetmal,
If your music is in MP3 or iTunes format, it's not going to shrink down much more that it already is. That said, burning to multiple recordable DVD media is going to be your best bet.
I would also consider purchasing an external USB hard drive. You can get a 40-60GB external USB hard drive in the $40-$50 price range.
http://www.newegg.com/Product/Produc...=%2425+-+%2450
- John