S'cool! Reading through this thread might help you get an idea of what people consider realistic rates: http://www.ultimatemetal.com/forum/andy-sneap/571279-how-much-do-you-charge-5.html
If you've really been running your own studio since 2004, then by all means, you should be charging more than I do. For what it's worth, I've settled on my rates based on what other similar studios in my general area are charging, which in my opinion is still way too low.
Thx man, appreciate all the help. Studios my side of the word charge $450 a song, and it sounds so amateur IMO. But that to me is a mad price.