Interpreting Coefficients from wavelet The wavelet transform informs  what all derived wavelets (from mother wavelets) with different scales at different point of time , are present  (along with the associated strength) in my original signal.  I am not able to understand how do I now correlate it with FFT that simply gives what all sine and cosine waves are present. 

Now how do I make use of this information that I get from WT? I cannot say unlike as in case of FFT or STFT " we have a 100hz frequency in the window of 4 seconds". I will have to say "we have a db4 wavelet present  in some window". How it will make sense. How do I interpret this in a meaningful way?
Wavelets are used for time-scale, or time-frequency, analysis, just like STFT. You can map the coefficients of CWT to frequencies through the center frequency of the wavelet. See for example http://www.mathworks.se/help/wavelet/ref/scal2frq.html