GGRRR comp ate my post, hate that!

Bottles are similair to nappy's in the sense that not one size fits all.

DD1 would only take avent bottles, DD2 will only take the cheap happy baby bottles (yay for me!)

i would get a couple more bottles the ft ur breast pump, incase u pump and freeze the one u have and need to use it again.

As for sterilisers, we used the milton tub and solution. Didnt matter what size or shape the bottle was, it all fitted in.
its about $45 from bigw and im pretty sure that u can get it from chemists aswell.
HTH