Why not omit both the capacitor and OP amp output resistor and see if that helps - after joining all the grounds.
I just tried this, but to no avail. Still reading zero at the serial port, as well as at pin 5. Although, if I touch the multimeter to the output pin of the opamp I get the right reading, but it is not translating over to pin5, even though they are directly connected, which I confirmed by a continuity test. Could it be possible that i have somehow damaged digital pin 5?
Have you confirmed the transducer is getting a suitable drive voltage and is outputting a signal.
Yes, I have confirmed that the transducer is getting suitable voltage.