Gim,
I hope you'll enjoy you stay in the World's Most Livable City (according to a poll a few years back).
You haven't mentioned wehther it's day trips or overnighters, and also whther you want to do some touristing as well.
For day trips I'd suggest the Yarra Valley; or take a trip up the highway to Nagambie and visit Tahbilk and Mitchleton. You can travel on a riverboat that takes you between Tahbilk and Mitchelton as well. You can lunch at Kirwins Bridge or Mitchelton.
For an overnight I'd suggest Pyrenees and Great Western. This will also provide tourist things as well; like the Goldfields City of Ballarat, and a bit of bushwalking in the Grampians if you wish. Staying overnight in among the vines at Warrenmang is also great and the restaurant is excellent. In the Pyrenees you have wineries like Dalwhinnie, Summerfield, Berrys Bridge and Taltarni, and in Great Western Seppelt, Bests and Langi Ghiran among others.
The Victorian Tourism Website
www.visitvictoria.com.au is a good resource. Click on "Food and Wine" on the sidebar, the Wineries. I've discussed some in Central Victoria and Western Victoria.
In terms of Wine Courses I'm not sure, most are multi-week courses so there may not be one that provides an overview of Australian wine timed for your visit.
