try hand washing it in really cool water
then soak it in loads of softener
when you've rinsed it, lay it out flat. try to get it roughly back to its old shape by stretching it and putting weights on it.
that sometimes works if the shrinking wasn't too bad in the first place. but its likely that they're buggered
you really shouldn't be putting any woolen items in the washing machine miss scarlet! they'll live a lot longer if you hand wash them.