an RTI application cannot be filed against a Pvt. co. but the guidelines of the SC and the subsequent Act of parliament stipulates that there should be a committee in every co./workplace which should hear complaints against such harassment.
if your co. does not have it, it is in violation of the law.
a legal notice should be sent to the co. which is complicit in this matter and has aided the culprit in not facing the rigors of the law. there is no specific duration but you should file it instantly as the matter is still new and evidence etc can be found.