Contact all 3 agencies (Equifax, TransUnion, and Experian) and let them know that the debt is not yours, it is your father's, and that you have the same name. Include copies of any documentation that your father has showing the debt is solely his and the information should not be assigned to you.
http://www.myfico.com/crediteducatio...planation.aspx
Once the erroneous information is removed your credit score should go up. Figure on the whole process taking 60-90 days.