Hi Matt and
to the mad house.
Graeme is on the money there, the bigger the aperture the more you see. Not sure what your budget is or what the sky is like in Brisbane but I started with a cheap 4.5 " and was surprised with what I could see but moved quickly to a 10" to be seriously surprised with nebula views, dust clouds to be found and globs to drool over.
I'd also suggest an 8" or 10" to get properly started. With luck you can spot one going second hand on here in the For Sale section and when and if you get aperture fever it will always sell on to the next newbie with little loss.
Andromeda is northern hemisphere object, pretty low in the sky for us southern people but we have the best skies for many other objects. Better than northern astronomers.
Get Stellarium on your computer and set it up for your location and that will let you see just what you can see at our end of the world. Heaps !!
Keep us posted on what you do and ask questions. Any body here will have some useful advice. Get yourself along to your local Astro Club open night or club night. They should happily let you have a look through various scopes so you can see what is possible. They may even have scopes to rent for a month or so and you can try one or two out.
Good luck and have fun.
Cheers
Brent