If you can afford a lawyer, a lawyer referral service can help you find a lawyer who has experience in this area of law. You may want to ask the lawyer referral service whether they screen for lawyers who are experienced in handling domestic violence cases -- not all lawyer referral services do this.
If you can't afford a lawyer, you may be able to get help from legal aid, who provides free or low-cost legal help in some cases. If they can't help you, they might be able to refer you to someone who can take your case on a sliding scale fee or for free. Some legal aid organizations that can give referrals don't advertise that they do - be sure to specifically ask for a referral if you need one.
Shelters and other domestic violence or sexual assault organizations may also be able to provide you with a referral for someone who can take your case for a lower fee.
You may also want to try any law schools in your area because sometimes they have legal clinics and can take cases for free.