Hey liz have you tried taking it apart to see where it is leaking from? You might not need a gasket. You can get gasket material from an auto parts store to make your own.
Those bings have issues with the float. Check to see if the needle and float move freely. There are lots of options if its a gasket, that would get you through the weekend.
If you have not taken apart a carb before moped junkyard actually has a good diagram of that carb in pieces.
Well have to go to work. Good luck