I keep reading that breastfed baby's stools aren't realy stools - more of a puddle, which apparently is good and helps their digestive systems.
So the books say the formula fed baby has harder stools and is more prone to constipation.
Now i've not had mine yet and could be wrong, but sounds to me like she is doing great, but if you are worried give your doc/midwife/mum/aunty a call and see what they say - often best to see what others did at same age.
But i'd guess at if she looks well, feeds well, and puts on weight then you're definately doing things right.