Great job getting your finances in order! Unfortunately, you usually can’t remove cosigners from your loan. However, you may be able to remove your father from the loan if your agreement includes a cosigner release clause.
Since refinancing involves taking out a new loan with different conditions, it isn’t exactly taking someone off your loan. However, you can apply for the new loan without a cosigner, and you could get better terms and a lower interest rate. If you still don’t have stellar credit, wait for your score to improve before you refinance—so you can get a better loan.