Could someone help me out and tell me how I can both call and text to Australia?

The number is
4582154XX

I think I need to dial
011 51 4582154XX to get there but I'm not sure.

It's too confusing.

I don't have long distance phone service here at home since I have a Google Voice account. Having an $8.00 a month AT&T service is pretty nice.

Anyway, people on the web keep mentioning some 406 number texting trick but I don't have a clue as to what they are talking about.

Any help on this?

Thank you so much if someone responds.