i found one at Mills Fleet Farm of all places.. for hose not in MN or WI- Mills Fleet Farm is the greatest store ever- they sell tractor parts and grade 8 bolts by the pound- and pretty much everything else you need to live a happy life.
anyways, in the exhaust aisle next to the Flowmaster and Cherry bomb mufflers, they had gaskets hanging on the wall and i just matched one up and gave the checkout lady the $2.99 for the gasket. i had to slot the bolt holes a little bit for a perfect fit, but it seals. i don't know what it was for, and i really don't care. it fits.
but if you aren't lucky enough to have a Mills Fleet Frarm or similar store near you, i'm sure that if you take the flange to a good parts store, they can match one up for ya.