Not knowing much about batteries, I simply ring the NRMA and they come out, supply the battery and install it, they also check the charging circuits, alternator etc.
When you ring them, specify the car and request the best battery that they have, it will cost between $140 and $180, you won't be sorry. :(
Biggest killer for batteries is dirty terminals, oxidised, make sure that they are clean even to the point of replacing the battery terminals, they cost about $5 to $10 each for the good ones.
Peterp