Usually babies double their birth weight
by 5 months. So when she completes 5 months, she must be roughly around 5.6 kg.
By now she must have social smile and good head control. If development is okay and she is active- you need not worry.
But feeding is not okay. Exclusive breast feeding till 6 months of age is the best for your baby. If you are taking a nutritious diet and have adequate rest, there is no reason for your breast milk to be low.
And its better not to give any animal milk till 1 year of age.
Try to put her on exclusive breast milk till she completes 6 months. After 6 months, you may start weaning her on home made food.
If you have no other option than to supplement her- please opt for formula milk. They are at least close to human milk in terms of nutrients.
Hope i have answered your query.
Wish your baby good health.