Custody

I'm going to be moving back home in with my mum the middle of next year. To the same town that my ex, who is my daughter dad, lives in.
Im so broke I don't have a choice.
We live interstate and don't have any one eles to live with, we actually don't have any family or friends where we are.
My daughter when we move back home will be nearly 4.
She has never meet her dad (as I call him a sperm donor).
We were together 2 years. We stayed together 7 weeks of the pregnancy.
The second I found out and told him he said what are you going to do with it you can't keep it. He wanted me to have an abortion. Rang up a clinic to do it. Told the lady when she came back with a date which was in 3 weeks time it wasn't soon enough. I rang her and apologized for his behavior towards her. So he found another place. He drove me there paied for it. I cried the whole time saying to him that's my baby that's my baby when she was up on the ultrasound. He crossed his arms and shook his head.
The lady didn't let me go though with it. And I've been forever greatful for her.
When we got home he made out how amazing it was going to be. But he became physically violent. He threw me across the lounge room. He pushed me into things. Pushed me over. Climed on to my back telling me I'm going to loose the baby cause I'm so shit.
He soon locked me in the house breaking my phone and car keys. I was trapped for weeks.
I took out a restraining order but it went on for 18 months. It got to final hearing. I wasn't strong enough to keep going on the stand so I walked away.
Now he doesn't even have that against his name to ever back me.
I was made out to be the crazy one. The one he trapped in the house cause I was trying to kill my self. He held me down because I was going to cut my self.
He broke my eye because it was dark and I rolled into his elbow. I'm the crazy one and his the hero and it was never prove other wise.
His never asked to see her. His never messaged or got legal help.
He isn't on her birth certificate.
His off with a new girl his been with since I left at 12 weeks pregnant.
He sees his other daughter but he left her when she was 2. So she knew him.
Now if I move back home and he decideds after 4 years it will be nearly 5 when I'm home including pregnancy time that he wants to see her what rights will he have??
Has any one else been in this situation?
I'll be seeing a lawyer soon but I just wanted to know if any one else has been here?
I've protected her for this long.
But I need to move back home. I feel like I'm failing her but ny mental health is at a low a very low. I'm raising her on my own and its looking like she has sensory processing disorder. I can't afford her specialist appointments any more I've had to stop them. I can't afford my rent any more either I'm behind now. I can't mentally support us any more. 3 years on my complete own and I'm done. I don't get a break. Always on the go. Single mum's you get this. It's so fuckn hard. No one to even call in on and just have a tea with. I need my family more than ever.
What right do you think he has? Do I just keep denying his the dad. Thats what his telling every one that I left cause he wasn't the dad and I was ashamed. But he can easily turn around and say I just really want to know if I'm her dad. And it makes me so mad when I'm her mum and I've done everything for her and never got or asked for a cent out of him.
She's my baby I love her more than anything. He will just want to see her to upset me.
So what are the right of a sperm donor (father).