Your voice has so much potential. I personally think you began a little weak and unsure, but as you got into the song, you improved dramatically. You genuinley have a good voice, the sort that could arouse tears in someone when singing the right song i think. I agree with ThatisDumb, a few classical lessons may give you a booster, because you have all the potential, but you definitley seem a little uncertain on higher notes. I've listened to a few evanescence covers, and to be brutally honest most destroy them, but you've really done this song justice. Work a little on those unsure parts and you'll be even better than you are now!