Where are you located, in the US or somewhere else? If you're in Europe and you plug in an adapted that's only expecting 110 volts from the wall jack, but get fed 220 instead, it's not going to be happy.
Your safest bet is to get an official replacement from Nintendo.
I am in India.My Wii Expects 110V and I will be giving 110V but I am worried about difference between Ampere ratings.
ie 3.7 A and 5 A. Will it make the difference.