Will God take revenge on my behalf upon the one who wronged me after I supplicated against him, then forgave him, and will I receive the reward for forgiveness?

That Allah Almighty takes revenge on the oppressor or forgives him is a matter of the unseen. If you forgive someone who has wronged you, you will be rewarded. It is hoped that Allah will drop your right against the oppressor due to your forgiveness, while Allah's right remains, which is dropped by repentance. If the oppressor dies before repenting, then his matter is with Allah Almighty; He may punish him if He wills, or forgive him if He wills.