What should one do who vowed to donate a full month's salary if a certain matter was fulfilled, then Satan made her forget it? Should she donate the same amount or more? And is it better to give it to feed the poor during Ramadan or to her needy aunt?

A contingent vow is disliked (makrooh), but it must be fulfilled if the condition upon which it was made is met. You are required to pay a month's salary to fulfill your vow, regardless of changes in currency value. Delaying the fulfillment of a vow when one is able to do so is not permissible, but you are excused due to forgetfulness. If you did not specify a recipient for the vow, and your aunt is in need, it is best to give it to her.