> How from ...1024 or 2048 or 4096... FFT return values i calculate
> power magnitudes for all bands,
> and finally values for visual 10-20 hopping bars, like in Winamp ,
> XMMS , QMMP ... ?

If you want such a display the FFT is not a good way to do it.
It's possible but not simple if you want a correct result.

> 43303.2715 + 796.7285 = 44100 or 44100 - 43303.2715 = 796.7285>
> Why Frequency 796.7285 is mirrored as Frequency 43303.2715 , and magnitude for both Frequencies is divided by 2 ????

Because you are using a complex FFT, and the imaginary part
of your signal is zero. That means that the spectrum must be
symmetric.

> Is here way direct calculate full magnitude and without Frequency
> mirroring , in band 0 Hz ... FSampl/2 ONLY ,

Use an FFT operating on real data instead of complex.