May seems weird but check your hearing and speech centers. They may have resources or even provide them outright. My does provide ASL interpreters and that where the Community College "outsource" if they are "low" on "in house" ones.
You could also load up the search engine and look for that online like "how to get ASL interpreters for a public event" or something.
Try to type "Deaf Interpreter Agency South Carolina" in google search. You might see the list of the addresses. I see an agency near Charleston, South Carolina.
I had NO idea what you meant when you said "Terps?" lol I thought you were saying something about someone is a terp or something along them lines. buwahahha! silly me. I didnt read your comment correct.