The filter disks
can be found in a lot of supermarkets. Look for percolator filters made by Melitta or Mr. Coffee. I have never had trouble in finding them.
I have a few of these machines, and use one every so often. They brew hot (just checked one that I have in the rotation, and it is rated at 1500 watts), and I have always found the coffee to be decent. Just make sure to grind your coffee a little on the coarse side. The instructions that came with mine states that the machine works best with Maxwell House ADC coffee, which I found interesting.
Remember that these came out at the beginning of the auto-drip era, so none of the bits that we are used to today are to be found on this. There is no drip stop for a quick sneak of a brew, the grounds basket sits on top of the carafe, there is no timer, and no switch (as mentioned above, simply pull the plug).
That being said, the machine takes me back to another time, and with its black plastic, brushed metal trim, and sturdy 1970s era carafe, it looks great on my counter.
By the way, the date on the instruction leaflet that came with my machine is dated 1976.
I hope that you get the machine, and that you enjoy it.
Joe