How to find the order of Band pass filter?

Hi guys, I am actually constructing a code to seprate a sound signal+noise on the basis of frequencies present in the signal. I have almost completed my code but now I exactly want to calculate the order of my band pass filters which I used in this code since by now I used hit and trial method to find the best suited order. Can anybody tell me how to exactly calculate the order "n" of a band pass? I have used to filters since my signal contain two peaks, one at 1000Hz and other at 2000Hz. My code is as under.

[y,fs]=wavread ('sampledata.wav')
% soundsc(y,fs)
t=0:1/fs:(1-1/fs);

fr_y=fftshift (fft (y)/length(y));
x_axis=2*pi*[-length(t)/2:1: length(t)/2-1];
abs_fr_y = abs(fr_y)
plot(x_axis,abs_fr_y)
y1 = awgn(y,(1-1/fs)); % Add white Gaussian noise.
figure
fr_y1=fftshift (fft (y1)/length(y1));
abs_fr_y1 = abs(fr_y1)
plot(x_axis,abs_fr_y,x_axis,abs_fr_y1)
legend('Original signal','Signal with AWGN');

   band_pass_fil1=fir1(1000,[(2*990)/fs,(2*1010)/fs]);                        
   band_pass_fil2=fir1(1000,[(2*1990)/fs,(2*2010)/fs]);        
  sig_1 = filter(band_pass_fil1,1,y1); 
  sig_2 = filter(band_pass_fil2,1,y1);
  sig_1_f=fftshift(fft(sig_1)/length(sig_1));
  signal_1 = abs(sig_1_f)
  sig_2_f=fftshift(fft(sig_2)/length(sig_2));
  signal_2 = abs(sig_2_f)
   figure
   plot(x_axis,signal_1);
   title('Filtered Signal of "1000Hz"')
    figure
   plot(x_axis,signal_2);
   title('Filtered Signal of "2000Hz"')