Hi Cossoft...
reckon if you changed the anode resistors you'd be in a more sensible part of the characteristic....
perhaps about 10k .
the anode current will be about 3 mA, the Gm about 5mA/V giving a gain of about 50x per stage.
edit : and g1 will be at about -3V compared to the cathode.
then 50x50x15mV gives a p-p at your arduino of about 3.75V - right sort of ballpark.
If you want a bit more, increase the anode resistors.
edit : Obviously you'll have to bias the capacitor-coupled input to the arduino with
a pair of resistors to it's mid-rail - suggest 2 100k's . This appears at ac in parallel with the anode resistor, reducing the gain of the second stage by about 20%, so I'd make it's anode resistor 12k as a starting point. I'd suggest the coupling cap about 3.9nF to make the LF -3dB point about 1kHz.
good luck - let us know when you've tried it!
regards
Allan