What is the expiation for one who had intercourse with his pregnant wife during the daytime in Ramadan, and is it permissible to offer it after Ramadan when financial circumstances improve?

If a man has intercourse with his wife during the daytime in Ramadan while he is fasting, he must make up that day (qada') and offer expiation (kaffarah). The expiation is to be performed in sequence: freeing a slave; if he cannot find one, then fasting for two consecutive months; if he is unable to do that, then feeding sixty poor people. Whoever is able to hasten the expiation is not permitted to delay it. If he is unable to perform it, he should do so whenever he becomes able. The wife is similar in all of this if she was compliant, according to the

view that expiation is obligatory upon her.