What do I do with the result of an FFT?
I would recommend doing some proper reading of books/tutorials etc on the Fourier transform and the Discrete Fourier Transform (DFT).  You will also want to look at filters and probably convolution for the bandpass filter.  But regardless, here's some info that should help with your current state:

Use matplotlib to plot the FT that you've calculated:

fs = 44100 # Or whatever the actual sample rate is (Hz)
f = linspace (fs,len(data), endpoint=False)
mpl.plot (f, abs (fftres))
title ('Magnitude spectrum of the signal')
xlabel ('Frequency (Hz)')


Another function you will want to look at is fftshift, which makes it simple to 'roll' your spectrum around so that DC is in the centre.

The frequencies that are sampled by the DFT are between $-f_s/2 &lt; f &lt; f_s/2$ for sampling frequency $f_s$.  And the FFT produces the same number of samples as the number of data points provided to it.  The FFT function returns the spectrum so that the DC (constant/average) value is first in the array.  Use the function fftshift to adjust the array if you want it ordered  $-f_s/2 &lt; f &lt; f_s/2$.

I will now repeat: Fourier transforms and filtering are a huge field, and while it will definitely be interesting and useful to play with the functions for a bit like you are doing, you really need to read up on what is going on if you want to actually do anything useful.

Aside: why are you starting at index 1 in your loop, rather than 0?