FD - Take them to Ina's shop, next to her Indian Restaurant. There's some nice gear in there. Up the hill, past Vassilis Fish Place, is Mona's Boutique and just opposite is another little place with "Designer Jeans" etc.
This might kill an hour or two. - Or hire a car and go to Acharavi ( About 20 mins drive) They have some good shops there as well.
Cheers
Negg