Thank you for continuing to encourage your friend to seek help-- that's very brave and noble of you. Too many times "friends" will just turn the other cheek when they know someone has a problem that they need help for.
You can continue encouraging her and also provide her with resources such as the National Eating Disorder Hotline at: 1-800-931-2237 (You can call this number yourself for some guidance on how to help)
You can also visit: http://www.nationaleatingdisorders.org/get-help-today/treatment-provider-disclaimer.php to find some providers and treatment information. You can give her the site as well to see if one day she will willingly search for help herself and she will know where to go.
I hope this helps-- thank you for not giving up on your friend.