J.P.
Hi--
The best way to do it is actually make your own formula. There are lots of recipes on the web of different ways to do it. Goat's milk is the closest thing to breast milk, so I am giving you a link to a goat's milk formula. Making your own is inexpensive, and you can control the quality of the ingredients.
http://oreganicthrifty.blogspot.com/2009/05/goat-milk-for...
J.