is this it? I got nothing for azoo palm filter 
http://cgi.ebay.co.uk/AZOO-Mignon-P...089?pt=LH_DefaultDomain_0&hash=item3f04c51f31

http://cgi.ebay.co.uk/AZOO-Mignon-P...089?pt=LH_DefaultDomain_0&hash=item3f04c51f31
i would get a piece of hard tubing, about 1 inch inner diameter and tall enough that the bottom of the tube would sit on the bottom of the bowl and the top of the tube would be at least an inch under water. drill a whole bunch of holes in the bottom half of the hard tube, plug the bottom end of it somehow (glob of silicone, rubber plug, etc). get a chunk of sponge, cut it to your desired shape/size, and bore a hole down one end of the sponge and shove the holey end of the tube into it. airline and airstone down the top end of the tube. done.
If you're handy and can find a small submersible pump, like the kind sold for tabletop fountains, you can make a canister filter. That would give you the maximum amount of room inside, since all that goes in the tank are the intake and outake hoses. If you google "DIY canister filter" you should be able to find a number of tutorials, there are probably some on AC as well.
looked at one tutorial and it seems much more complicatedlol