Sampled signal reconstruction using matlab
I'm not exactly sure what you mean by 


  I want to reconstruct the sampled signal


The term reconstruct has a special meaning in DSP and is related to converting a signal from discrete form to continuous using a DAC and a low-pass filter. 

I'm going to guess that you are just looking to plot the signal in time domain, and if that is the case then your code would look like this:

[y, fs, nbits] = wavread('signal.wav')
sample_period = 1/fs;                % sample period is just the inverse of the sample rate
sample_time = size(y)/fs;            % total time represented by the samples 
time = 0:sample_period:sample_time;  % create the time array
plot(time,y)