I've edited my post after time to think about what you actually want.
What you need are some basic calculations which are nicely laid out in chapter 1 of Prouty (Imperial units) or Leishman (Metric). These can be used to approximate the ideal performance of a helicopter. You'd be suprised how far you can take some of these basic techniques.
As a starting point for your theoretical design in hover assume (in SI units):
Engine power = Weight^1.5 / (2 x Air_density x Rotor_area)^0.5 Watts
In practice the actual power will be about 1.4 times that calculated due to the 70% efficiency of a practical rotor system. This is because the same aerofoil section, twist and taper must handle many flight conditions, so ends up a least worst compromise.
For engineering design performance calculations the accepted method is to combine vortex panel aerofoil sections with blade element momentum theory. You use the vortex panels to calculate coefficients of lift, aerodynamic centres, and drag (boundary layer seperation). The momentum theory then calculates the performance in hover, climb, forward flight, etc. This gets more and more complicated as you try to capture inflow effects and tip vortices. Ultimately to capture the dynamics of vortex ring state you end up using computational fluid dynamics...
So you can see that the subject starts off easy but can become complicated.
PS: I genuinely hope you have not been badly affected by the Tsunami - the news images look terrifying.