bOwtIewAgon/ looks useable. the front bolt might not fit original framework. drill a hole. set it on top to see how to make it work first. take yours off and make a bracket to set on the back of framework from bolthole to bolthole, then set the seat on that and drill where those bolts sit best. that will fix the crooked thing at the same time. here is a sample of what i mean

seat bracket - Copy.jpg