Is mediation a smart choice for me? (Custody)

My parents have custody of my daughter and have since 2004. This was due to my being arrested for malicious mischief domestic violence (I kicked the front door to my parents house and broke the door frame). I was arrested and left my daughter with them instead of foster care. At the time I was also addicted to meth. I've been clean for 4 1/2 years now and believe that I have proven that not only that I am capable of staying clean but that I have earned the right to regain custody of my daughter. I see her daily, take her to school, she spends the night with me on my days off, I have a strong bond with her. I've talked to my parents about re-gaining custody with no answer....Help please!