unfortunately, you will probably have to drive somplace. but you can't be that far from madison! there's dozens for sale right now at scooter therapy. seriously. contact them. we often drive far out of state to buy mopeds. so do that.
also, if you find a cheap moped across the country, you can get pretty cheap shipping via amtrak. you'll have to pick it up at a train station, though.
or go through the new mopeds, like vern suggests. they might be worth it. scooter therapy in madison WISCONSIN also sells new avanti (formerly garelli) mopeds. they might have some other new models, i just can't remember right now.