We have an opportunity to organize a seminar during the end of may in Novi Sad. You will be notified of the exact time of the performance in due course. Warm regards .
The meaning is ok, however I would make some changes to it: "We have an opportunity to organize a seminar in Novi Sad Aat the end of May.You will be prmptly notified of the exact time of the performance.Warm(Best)Regards."
Thanks.