Take a look around for your backup. It will be called nand.bin (keys.bin will work as well). If you find it you can have it flashed back into your Wii by a programmer (for a small fee of course).
If you softmodded with Mauifrog's Softmod any Wii guide you still have a trucha/dip patched IOS80 and this should work for you.
Mauifrog's Softmod uses IOS60-v6174 from Cioscorp patched to install to slot 80. If the OP used mauifrog's guide he has what he needs (besides possibly not having a compatible drive).
"Macs are the Perfect Computers," said the Perfect Idiot.