I really like the fellowship suggestions: inviting her to activities, calling her up to see how she's doing, asking her if she needs anything, being sincerely caring. Maybe you can talk with the RS pres. and ask about fellowship ideas. Also, encourage her to invite her friends and family to church. I agree with dorave, it might not be a racial issue keeping her from church. But if it is, I think it's ok to tell her that you too would hope to see more racial diversity in your ward.