Maria, as the spouse of a Spanish national (or even an EU national if they were resident in Spain) you have an absolute right to live with your husband in Spain. Spain signed an EU Directive which makes it illegal to prevent a married couple residing together unless there are extraordinary circumstances. My wife is Filipina. We married in Manila. Her visa was issued quickly and her application for RESIDENCIA was straightforward. She has been here 11 year and has permanent residency status.
You will need a visitor’s visa issued by a Spanish Consulate in Australia. When you arrive in Spain you must start proceeding to become RESIDENT, in your case that mean apply for RESIDENCIA, within the validity of the visa. That it expires after you have started the application and before your application is approved, is not relevant
Where to live: Unless you are fluent in Spanish, I would have thought that a place where English is commonly spoken would be a good place to live, so Costa del Sol, Costa Blanca etc. would make life easier
Item 4: A single EU national applying to become resident in Spain must show they have 366.90 € p.m income ; a couple 623.73 € p.m.
NB You of course, as a spouse of a Spaniard, will not need to prove your income. Those amounts are considered by the government to be sufficient to live on. I think doing so would be difficult, but hopeful that gives you an idea.
Good luck