The simplest solution for you, and one of my new favorites is a program called AnyRegionChanger. I made a guide for installing New Super Mario Bros (also on this subforum) so I'm going to lift the part that uses AnyRegionChanger out and just paste it in here, so excuse the numerical inconsistencies:
3.) Run AnyRegionChanger.
4.) When you get to the menu, choose “Install System Menu 3.2”.
5.) When asked if you’re sure, choose yes.
6.) If asked if you want Korean Disc Support, choose no.
7.) When it asks if you want System Menu Hacks, choose yes.
8.) When everything finishes, press any key and it will take you to its menu again.
9.) Restart your Wii
The program is called AnyRegionChanger because it's designed to let you install foreign regions onto your Wii, but that isn't all it does. When used with its defaults (and when saying you want system menu hacks) it keeps your 3.2U firmware (good) but updates all your IOS - system files - to run new games.
In order to run it, download it here, extract that to its own folder under the apps folder on your SD card, (for example, put it on /apps/anyregion), and rename the .dol file to boot.dol. Hopefully that isn't confusing. After you do those steps, just follow from my numerical list and let it work its magic. When your Wii is restarted, everything should be up-to-date.