Try
Brisbane Marine Pty Ltd
306 Duffield Road, Clontarf, Queensland, 4019
- Phone: 0738893033
they should have all the bits you need and can do your mech. repairs as well.
As for the impeller, most people will say you should replace your impeller yearly, having said that I have had outboards where I didn't change it for several years and it worked fine, however that is your call. Ask the the guys there, explain the situation and see what they say.
Regarding the battery, on my boats I just use a big AGM battery and never had dramas.
Brisbane Marine will also have hoses but you can also try:
Queensland House of Hose
4/15 Cessna Drive,
Caboolture Qld 4510
Phone: 07 5499 3500
Cheers
Ed.