All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is the duty of the husband to fulfill the rights of his wife and children by spending on them, taking care of them and educating them. This will result in a good Muslim family that can become an example for neighboring families. But this is not the case in the family in question. In fact beating one's wife and daughters and mistreating them contradicts the Sharee’ah. Allah Says (what means): {…live with them honorably…} [Quran 4:19]
Indeed, beating and mistreating them cannot be considered part of honorable company. Now, we advise you, dear sister, to remain patient for the sake of her children. You should take some steps that could help change your husband's behavior. You should call him with kindness to perform some good acts. You may also seek the mediation of some relatives or neighbors who would try to settle the matters that are between you and your husband and exhort him to do that which will benefit him.
Now, if your husband persists in his wrong doings while you can no longer bear what he does to you, then weigh things out. You should balance between the advantages that you will get and the disadvantages you will incur from the separation and take the right decision.
Allah Knows best.