The Japanese greeting cards are written from right to left, from top to bottom, therefore 右（から）here means "as stated to the right" and refers to the contents ("this"). It can also be used if the card is not vertical, simply meaning "as stated (above)". まで here means "only" making the phrase more humble as if asking for an excuse for hurried or less courteous notice. まず is used at the end of letters and means "anyway", "to wrap things up" or "for the time being"