You have three choices:
1) Triiforce
2) uLoader (Easier to set up, so I would recommend this)
3) UNEEK
Choose what you want, I think ModMii can help you with the setup, at least for 1) and 3). Oh, and don't use wad2nand, it's old and doesn't do it's job right, use ShowMiiWADs instead, which does everything as it should.