It's time for you to plant sweet peas, strawberry runners, spring bulbs, trees, shrubs and vegetables according to climate. The following vegetables are what we plant in our autumn/fall:

All Zones – beetroot, broccoli, cabbage, carrot, cauliflower, celery, lettuce, radish & spring onion
Tropical - capsicum, cucumber, eggplant, French beans, garlic, kohl rabi, leeks, lettuce, potatoes, pumpkin, silver beet, spring onion, squash, sweet corn, sweet potato, tomato, zucchini
Subtropical - Brussels sprout, capsicum, endive, French beans, garlic, kohl rabi, leeks, onions, potatoes, silver beet, spinach, sweet potato & tomato
Cool Temperate –broad beans, kohl rabi, parsnip, silverbeet & turnip
http://www.annettemcfarlane.com/calendar.htm

Check out the seedlings in your local nursery. Any they have now will be suitable to plant.

Other fall garden chores include trimming of any plants that have become rampant over summer as well as lifting, dividing, propagating and replanting of any herbaceous perennials.

As for black plastic, I guess that's a personal choice. I've been busy over the years ripping it out of every garden that I've found it in but if you hate the idea of weeding, then use it. Make sure it's thick enough to prevent the stronger weeds pushing through and cover it with your choice of pine bark or white pebbles. Pine bark being the cheaper option.

Happy gardening.