A lot of times, the feeding guidelines listed on food bags say to feed a lot more than you really need to. The more you feed, the quicker you'll have to buy a bag a food again if that makes sense. You may have to do some experimenting to see how much your baby really needs. It sounds like you put down what the bag recommends, but she doesn't eat it all. You could try cutting back little by little until you get to an amount where it seems like she's eating it all or most of it at least.
Blue Buffalo would be an excellent food to chose. There are better foods, but Blue isn't as expensive as them and is affordable. Plus, since you'd be feeding a better food, you actually end up having to feed less of it since the quality is so much better. If you do switch foods, make sure to do it gradually as you don't want to upset your baby's tummy. Usually over a period of 2-3 weeks works, some can do shorter, some need longer. Start with 75% old food, 25% new for a few days, then 50/50, then 25/75...etc. You get the idea!
