I think it is extremely unlikely that your child will contract oral herpes from this day care provider. If they are washing hands, using gloves while diapering and not kissing the children, there is not a risk for your child. I would ask these same precautions of a parent with a cold sore, nothing more. If your child touches the face of the person with the cold sore, your child will likely not becoming infected anyway because virus cannot easily enter hand skin. I also think since you have talked with the director of your day care center, they are on high alert about the behavior of this provider and are likely being very cautious.
Terri