I Recently visit towncars and they are economical as compared to other, I also found Limousineaustralia where you can book online Audi, BMW, Limo in Melbourne, Sydney, Brisbane.
If anyone is interested they can use code egps1 for $20 bucks off their first ride (anywhere in the world!). I'll get a credit too if you use it!
It is now, they recently changed the referral amount.
But I have had friends use it in countries other than Australia, so it's not just for use here