To dial a number in another country, you first dial the international access code for your country, then the code for the country you're calling, then the actual phone number, usually omitting the first zero if any.  
You can replace the international access code with a **+** on mobile phones.

The [international access code for the US][us_iac] is **011**.  
The [country code for Australia][au_cc] is **61**.

So that would make it **011 61 131542** or **+61 131542** for your example.

However, that may not work. The Australian equivalents of the US 1-800 numbers are [13 numbers][au_13] (as well as 1300 and 1800), as is the number you want to call. They are charged at a local rate to the caller. The downside is that they're often not available from abroad, likely because the owner is charged the actual cost of calling the number.

----

However, Kia has [a dealer locator][kia_dealers] that shows phone numbers for those dealers. Those seem to be regular phone numbers that _are_ callable from outside Australia. Pick one of those and call them, either doing your business with them directly, or asking them for a number to call from abroad.

Alternatively, you can call Kia USA and ask them for a number to call Kia AU on.

[us_iac]: https://en.wikipedia.org/wiki/List_of_international_call_prefixes
[au_cc]: https://en.wikipedia.org/wiki/List_of_country_calling_codes#Zone_6:_Southeast_Asia_and_Oceania
[au_13]: https://en.wikipedia.org/wiki/Telephone_numbers_in_Australia#Local_Rate_and_FreeCall_numbers_(13,_180)
[kia_dealers]: https://www.kia.com/au/shopping-tools/find-a-dealer.html