How can i track my real dad down with no information about him ?

I am 20 years old and for 20 years i thought that the man who raised me up was my real dad , that was then he started abusing me when i was 8 and i have only got away from my familly , now i have been told that he isnt my real dad by my mum and i have asked her but she chooses to ignore me because she thinks im lying about the abuse . . . i just want to track my dad dwn but dnt have any infomation is there any way in getting help !!