Hi Renae
I don't think you can get a 60 day on arrival unless something changed in the last month or so that I'm not aware of.
If you want a 60 day you have to get it before you leave Australia - as you are on the Gold Coast the easiest way would be to send away for it, see here for details:
http://www.kemlu.go.id/canberra/Pages/ServiceDisplay.aspx?IDP=7&IDP2=17&Name=ConsularService&IsRootWeb=false&l=enOtherwise, you can get a 30 day Visa on Arrival for USD25, which you can then extend at Mataram immigrassi for another USD25 (or approx Rp 250,000). As you stay in Kuta that is a bit of a pain, especially if they decide to make you "come back in 3 days" (their favorite way of processing, especially if they think they can extract "hurry up" money from you).
Personally, for a longer stay, I'd pay the AUD60 and get the 60 day tourist visa.
Unless you think there is any chance that you might want to stay longer than 60 days - in that case, get a Social Visa which is also 60 days and costs the same as the 60 Day tourist visa but is extendable out to 180 days. The 60 day tourist visa is NOT extendable, and legally cannot be converted to a Social visa once in country.
A social visa will require a letter from your sponsor (e.g. husband). If you need an example of a letter pm me.
Also, my understanding is that the cost is the same for all persons, regardless of age.
Hurry up the new immigration laws that will allow all us bule married to Indonesians to get a resident visa, even when we don't live permanently in Indonesia - it will make all this sooooo much easier!
Freo