Cleaning signal, what do you think?
Firstly, you need to apply a small negative supply to pin 4 of the op-amps or you'll only be amplifying half the waveform.

I also think that the third stage from R2 to the present output should be your input stage and this can be followed by C1 and R1. If you must, apply an output buffer here to preserve the impedance of R1.

Always best to amplify up front for best signal to noise ratio.