she should be around 8 kg by this time .
as per growth charts she is in lower normal range.
But current weight depends on her birth weight and parents skeletal structure too.
when the child is developmentally normal and active .. do not think of weight :)
babies tend to take less amount of milk after introduction of solid food when compared to exclusive milk days
Next Steps
put some Ghee in whatever she eats .. it helps her in gaining weight
Give her jaggery
iron rich diet - green leafy vegetables
proteins - dal
egg after 10 months of age