I did it very simple way - one channel of jack [line-in] was held by yellow (DATA) cable. Other one was GND near battery.
I've used 2xRCA->stereo jack cable.
Hopefully I'll record some more (I have problems with sticking the wires to RCAs ;-)) and get readings also for CH1 and CH3 to see what's the difference.
At this point, with the pattern above - is it possible to modify your code to get the 0 and 1's from Serial with Arduino?
It'd be much easier to note down values of Temp. and Hum. using a notepad and ctrl-c ctrl-v. 
Even from a fridge etc.