Naku pare... delikado yan. Not only because the Wii's power was disconnected during update, but also because you tried to upgrade the firmware (presumably to 4.1) while some homebrew apps are preloaded.
Did you conduct some research about your homebrew apps prior to upgrading your firmware? Are your homebrew apps compatible with 4.1? Chances are, no. There is a special process when it comes to upgrading to 4.1 with pre-existing homebrews. Did you follow a special process?
Anyway, try any of the following:
1. When turning on your Wii, hold the reset button. What will appear on screen? With some luck, you'd hopefully reach an preloader menu which will allow you to restore the update. If the preloader appears, post back. If this preloader menu doesn't appear, read on...
2. Is your Wii hard-modded, i.e. is there a mod chip installed? If yes, google "Universal Unbrick Disc v2." Download, burn to DVD, then insert on your Wii. It should guide you on-screen with regards to the steps you should take.
Good luck!