Sure - see this Apple Support Article and the screen capture from my iTunes Preferences Advanced dialog box (arrow) - note my user name has been covered.
You'll just need an external HD (if that is the storage device you desire) and then follow the steps in the link; however, keep in mind that if you travel w/ your laptop and want to listen to music, then you'll need to carry the HD along; depending on the size (and future size!) of your iTunes media folder, a large capacity SD card or USB flash drive might be a better option.
Good luck and let us know if you still have questions. Dave