haha well, i'm not sure my vocal advice would be the thing. i'd send you off in prima donna direction...
breathing exercises are always good though - any vocal line is improved by continuity and evenness of breath, no matter the style, and good control of breath will free up the top of your range. try this one: inhale as deeply as you can, "into your diaphragm" as they always tell us, so that you feel expansion all around your waist (rather than the whole shoulder-raising deal). then start counting out loud. count as far up as you can, until you absolutely cannot eke another molecule of air out of your lungs, and then immediately take another deep breath and do it over again. slowly, you should be able to start counting for longer and longer periods of time, which will indicate an increase in breath control.
yeesh, that was long. sorry :-/