OK, a decision had to be made, and I've ordered a Billion 7202G wireless modem/router and a Netgear WG511 for B1 to pick up for under $200 total. She should pick up $40 for the old unused Billion ADSL modem, so all systems should be go.
Thanks to all for the advice.
Agent86, the iBurst technology looks like that at
Unwired which is apparently available only in parts of Sydney atm. Interesting; it would seem to be the way of the future. A little over the top for B1 at this stage though.