How can I expand my vocal range by at least half an octave?

I'm not bashing here at all - but I would not recommend yelling a song. It's not good for your vocal chords. But you can increase your natural singing voice with vocal exercises. That means lots of vocalizing practice by doing scales - up and down - stretching and relaxing your voice little by little so no damage will occur to those precious "chords!" This isn't just "days" this is a forever routine for singers. Vocalizing should be a daily chore to keep your voice fit. Just like a body builder exercises everyday for the same reason FITNESS! Good luck - I know you'll get there (Please don't YELL!)