Take it easy hipopp - baby steps. Bass Strait sailing is perfectly doable, but you must take your time to learn. First learn your boat from top to bottom in WPB, in calm conditions, then in 10 knots of wind, then 15, 20, 25. Learn sail rasing/furling, reefing, how do do it if the engine fails, anchoring, how to fix basic engine problems, the electrics and electronics etc etc. Always have a plan B and if possible a plan C whenever you sail, even locally. It's a really good discipline to get into the habit of contemplating these even on day sails.
Learn all about the very strong tides there, and how to find shelter if your engine fails, or you get caught by a blow, or stuff up the tide times and can't get back under the bridge. And develop an obsession with the weather and forecasts. Watch the forecasts every day, sailing or not, then the next day follow the actual observations to see how it works out. There will be local (katabatic) wind effects that the BoM won't describe, so talk to locals in the marina and elsewhere. These days the forecasts are so good, you really have to be a bit of a dill to be out there in weather that's beyond your abilities.
Eventually you'll be ready to head out. I spent 4 years in PPB learning before my first trip to King Island. You're very fortunate at Newhaven as you can poke your nose out for a quick looksee and scurry back into Cleeland Bight and change your undies if necessary (but obviously not in a howling northerly).
And as Chris 249 said, get a tiller pilot. It will take 1/2 a day to install and then you're good to go solo while you learn. It will take months to find and fit a windvane. I've done many Bass Strait cruises with tiller pilots and no windvane.
And buy a copy of the CYAV's Cruising Victoria book.
www.cyav.com.au/cruising-victoriaEnough from me, I'll shut up now. Good luck, enjoy!
Graeme