We're all in the dark about what the song is. Depending on what it is, and its character (aggressive, melancholy, humorous), various approaches could be taken. If it's either romantic or melancholy, for instance, you don't really have to hit the high notes hard at all--just touch them. If the song is aggressive, of course, this doesn't work. In general I would think the low notes are probably more important-- (but of course, as I said, none of us know what the song is, which makes advice difficult.)