Work accident/Incident

I worked as a residential social worker at a children's care home, and was run over by one of the residents just at the end of the drive, about 10 metres onto the main road. I broke my leg in 5 places, tibia, fibula during the accident and the child then attacked me with a hammer while i was on the floor. This resulted in broken ribs.
My employer paid me only ssp of about ?60 per week, and I had just taken on a mortgage.
None of my colleagues attempted to stop the child from gaining access to the tools, through two locked doors, and they have all banded together to discredit what happened. Their witness statements at work in no way reflect their police statements, which i will be relying on at trial, if it comes to that.
I was wondering about any figure anybody could put on my possible compensation, bearing in mind I have been assessed by medical experts to have only 70% use in my right leg now, nearly 4 years after the accident. I have also been diagnosed with sever PTSD, and still have trouble sleeping and nightmares. I have had anger management therapy, but still need some help. I think I need to finish this case to be able to put it behind me, then I can move on with my life proper. I have started University and begun new hobbies, but still need sme closure to be able to put this behind me. Any comments appreciated.
Cheers muchly

Dan