Hi Polly,

I can't really tell you anything, you probably don't allready know. The song sounds great, but I can hear what you're saying about getting the vox more punchy or screamin'. This sounds like a live recording, but otherwise I would think there are methods to get it done by recording, processing your vox.

If it really is the vocal technique you'd like to work on to get it right for your ears, I know a couple of great ressources that might help you. Catherine Sadolin is a danish singing instructor who has worked out some techniques that might suit your styles very well. The book etc. is available in english - Check out her Utube videos here:
http://www.youtube.com/watch?v=K1qkiaa15Vg

And her book here:
http://www.completevocalinstitute.com/

Good luck..