I understand you're nervous, however fire emanating from the GPU is likely unrepairable.
With respect we've given you answers based on the minimal information you have given us. You have either connected the wrong PSU connection into the GPU, have an incredibly poor quality PSU (which it appears you actually don't), or the GPU was faulty.
Fixable? Not likely. But if the GPU was defective, the manufacturer are liable to repair, refund or replace it. So you can send it back to the manufacturer.
I feel for you that this has happened, however your next available options are ultimately limited. But I do hope that it was just a faulty GPU and therefore it can be replaced free of charge.