At first I didn't know what you were talking about when you said Donkey Konga "3", because I thought they stopped at two, but then I saw that japan released a Donkey Konga 3. so yeah, whoops. Japan...those guyz are too kewl.
Anyway, yeah, if you just search google, or any other preferred search-engine the following : 'Donkey Konga 3 iso download'
If you did that, chances are high you will find a link that will allow you to put that .iso file on to an SD card and then into your freeloader thang.
Personally I like Guitar Hero better, but Donkey Konga at the time was the bees-knees!! idk...