Ok, I've read the document...a few times, hehe. And came to this conclusion...
I should use a JFET Op-amp because of the low noise, which is rail-to-rail and through hole (because I don't have a reflow oven). It also has to have a single voltage supply (5V) so I chose the AD820 for this...
Also made a diagram, instead of picking one from the internet (won't be doing that again 
)
The feedback resistor value and capacitor value are still a guess, but I think the filter is in the right place...Please correct me if I'm wrong.
