Animal Crossing: City Folk is not a downloadable game.  It is available as a disc in a physical package.  Here is information about the game from Nintendo: http://animal-crossing.com/cityfolk/

Are you sure that the Wii online store said that AC: City Folk was under WiiWare titles?  I doubt that it would be under that category becuase physical games are not called WiiWare.  Perhaps you were reading about the additional downloadable online content that is available for the game.  More information about that content is right here: http://animal-crossing.com/cityfolk/connected/

Also, you can find the game on Amazon or at a large retailer (if you are in America) listed here: http://www.nintendo.com/consumer/retail/retail_retailers_product.jsp?itemid=CyRXNiuwtxm0AgyMbOyehZ7N5f4JwIPy&title=Animal+Crossing:+City+Folk&platform=Wii