Homeopathy will do nothing for head weight. She needs physical and occupational therapy to strenghten her neck muscles so she can hold her head up and continue to learn to be mobile.
I will tell you that crawling is difficult for most of us. I'm 41, dx'ed at 3 weeks old, and never crawled. I was a butt-scooter and then one day, just before 2 yo, got up and walked. Because of her head size and weight, it will take some time for her to be able to develop the strength in her neck, and eventually, she will compensate for her head size.
Also, her ETV should be monitored carefully, as they have an obscenely high failure rate in infants.
Good luck, and please ask any questions at anytime. I'll do what I can to help.
LIZARD