If the game is from your own disc dump (or is a "legit" game) you can actually install and run it without CFW (Mocha). If it isn't "legit" you could use Mocha, but other options include Haxchi, CHBC (be careful with it) and Simple Signature Patcher.
The latest version of WUPInstaller Y-Mod can be found on the Homebrew App Store. wiiubru.com/appstore (also see the Wii U homebrew app that automates installation of apps for you)