I don't think that your daughter requires supplements at this age (unless she is having a deficiency of
calcium and phosphate). I would instead advise you to breastfeed her till she is 1 yr old (at least). That contains all the nutrients required for a healthy growth. And after she is able to chew, you can slowly introduce solid foods in her diet. As far as her legs are concerned, it is common for her age as her bones are still not strong enough. You can however use baby walkers for her, which will help her in developing the muscles and bones of her legs.
Next Steps
Consult your pediatrician for more details
Health Tips
Supplements should only be taken if there is a deficiency in the body. Otherwise it may lead to other complications. Remember too much of anything is bad for the body.