Did the questioner wrong her father's relative and expose her by accusing her of witchcraft based on a dream, and how can her right be restored after she caused estrangement between her relative and her father, despite having asked for forgiveness from her?

It is not permissible to accuse a woman of witchcraft based on a dream, for a dream is not a legal proof upon which a ruling can be based, and the dreams of those other than prophets do not constitute a basis for a legal ruling. You must repent to Allah and seek forgiveness from this woman for the injustice. Part of your repentance is to disavow your words in front of those with whom you slandered her, and to inform them that what you attributed to her was not true. The delay in marriage is one of Allah's decrees, so entrust your affair to Him, have a good opinion of Him, and increase your supplications.