Hello all, I also have been searching for this song since I first saw the aforementioned ad. Considering how nothing can be found about it, what I have concluded is that the commercial producers wanted to use an Evanescence song, but could not because either Evanescence's record label refused to allow it, or Discovery Channel simply didn't want to pay for it. Thus, the commercial producers probably requested that the audio production guys working for them supply a song that sounds to the effect of the Evanescence song that they had in mind. It could have been made in-house by the audio guys with hired studio musicians, or they could have found the song online or through industry connections. If you guys have been spending as much time as you say you have trying to find this song on the internet, then it probably didn't exist before the commercial; the producers wouldn't have spent as much time as you're spending to find the song to use. Somebody mentioned either on this or the Discovery Channel forum, that because the song sounds chopped up to fit in the commercial, that it probably wasn't made for the ad; I don't think that really means anything.
I'm pretty sure that the name of the piece is "I Run to You" or "Run to You", because that line is the last in the chorus, is repeated consecutively, and sounds like it is meant to be the hook of the song (even though everyone notices the "only time can turn against us". It's a horribly trite line and song name, and it's even a line from the song "Farther Away" by Evanescence (I haven't heard that song, but that is what I've found from Google).
If this song belongs to some unknown band out there, then this unknown band seems to be keeping it a secret; considering how desperate unknown artists are for publicity, it's very odd that they don't have enough of a presence on the internet to have one hit on Google, especially with this buzz about the commercial. If they were trying to cultivate buzz, we would know who we're buzzing about. Sorry if this is disappointing (it is for me), but unless announcements are made indicating otherwise, this song was made in-house for the ad.