I'll see if i can obtain a copy of the original bios for you and will update the thread in due course.
You can use ATIFlash, that's what i use when i upgrade my video card bios. It's much safer to do it via Dos than via Windows.
BTW,How did you pack the BIOS up to an auto-execute .exe file?
And how did you edit the fan curve?I wasn't able to find a working editor for this BIOS.