I need advice on how I can go about getting help for my daughter behavioral issues.?

[Alexa]

My 3 yr old daughter has been diagnosed with autism since 18 months old. But recently right before she turned 3 her behaviors and personality has dramatically changed. She has turned into this very violent and aggressive kid whose moods change like a light switch. She is self injurious and injurious towards others. Lately I've had to physically try restraining her for an hour long tantrums. Her behavior therapist doesn't even know what to do anymore. Her aggression has got out of control. My arms and face are covered with bite marks and scratches from her attacking me and trying to attack her sister and others. She knocked down furniture, dumped juice all over in public places, tore a chunk of her 2 yr old sister's hair out yesterday. Biting herself and me, hitting, kicking,... clawing, screaming all in public now too. This is usually on a daily basis or other day if I'm lucky. Today she threw the table over at breakfast with her eating program. She was just eating cereal then I guess suddenly decided that she didn't want it anymore and instead of using her words she freaked out. She had an hr long tantrum while I... tried restraining her the whole time wich is very exhausting cause she's very strong for her age. She hit her therapist and kept clawing biting trying to get out and then throwing stuff and hitting more. Then she got her arms out and took her little sister and through her down the stairs head first into a chair. Her therapist called the social worker up in concern for her sister's safety. When the social worker came to the house she threw a tantrum cause hse didn't want to share little ppl with her sister so she attacked again knocking down the big toy organizer biting clawing again as usual and she tried to bite my face. My arm bled from her and I have 2 more bit marks on me. The wrkr in his proffession admitted not even knowing how to go about getting her help cause that her issues are so uncommon for her age. I told him I've been trying to get her help for months since it's been starting and no 1 will help me get her a referral for a psych eval cause they all say she's too little and because of the autism! He said she could go away into a group home but most places won't take a 3 yr old and I refuse to let that happen unless it's the last straw. He said they're going 2 have to think out of the box on figuring out what to do about this with her. And that was just since yesterday. What is wrong with my daughter and how can I get her help. The proffessionals don't even know how to go about it. I personally feel there is something else going on with her besides the autism. Any advice would be lovely. Her issues are becoming a safety issue yet at the same time she can be very sweet. It's just crazy. She throws furniture hits, bites, claws, pinches, kicks, screams, you name it. But it's not just a hit and done with deal. It's an actual like attack where she'll keep going at you as the target and any1 in the way until she usually falls asleep or is too worn out. She acts like a feral animal not trying to talk bad about her but her actions are that way. Lik e the social wrkr put it "like a tiger fighting to get out of a cage". Her behaviors control my life now. I can't make any friends or have any over or go anywhere without the liklihood of hell breaking loose.