Hi Linda,
I don't think there is subsidy for formula through the Government for twins. There is the family payment that you should be eligible for though. Other than that, I know that if you can get a gp to write a script for formula (usually a special lactose free or protein free based formula) there is subsidy through the PBS scheme. Good Luck with the Breastfeeding! There are some really great tips on this site and also some legendary twin breastfeeders around who can give you lots of help!
LOL at giving your son a babydoll. Why not? In this day of equality?