The East Coast is beautiful - Bicheno - think you can do a night Penguin tour still and Coles Bay (walk into Wineglass Bay - need a day) Lots of other places too.
Cataract Gorge - Launceston. Port Arthur - Hobart. Wine tours. Cradle Mountain (might be something you would do in winter) Cruise on the Tamar River - Launceston.
Its very very cold in Tassie atm. If you dont like the cold, i would go anywhere from Nov -Mar. Starts getting alot cooler in April.

Lots of things to see.

Alot of people think that Tassie is very small and that you can see it all in a week - but thats not the case. You need longer than that to enjoy the scenery !