Jegs and Summit both show it as discontinued! This is not good. I have been using the same filter. Maybe a call to k&N? Other than that, take some measurements and get to searching Amazon and ebay for a replacement. There were a few on ebay in Australia for a ridiculously high price.
From memory, my 2007 CanAm Renegade 800 looked similar. I would start there or look and see what the current Kubota tractors are running.
Dave