1. Do I get any reward for the payment of this money to charity (or was the reward the happening of the event)? And if not, would it be better for me to break this oath, pay the penalty for breaking this oath and then still give the same amount of money in charity as I would under the oath, every month.
The oath falls in the category of Nazr. It is compulsory for you to fulfill the oath. Rasulullah (Salla Allahu alayhi wa sallam) said, Fulfill Nazr. One should not wait to give charity only though oaths. If the certain event in reference did not take place, then do not wait for that to give Sadaqa. You may do so from now. When the event takes place, it will be compulsory for you to fulfill your promise and continue giving Sadaqa as you were giving previously. Insha-Allah, you will be rewarded.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai