You will get the big problem now.When I exchange my H visa to F, USCIS request the whole payrolls till the date you were fired.So you must have your wife discussing with her boss and delay the date of her last month payroll.And notice this date must be after the date when your wife files her I539.Otherwise your wife will be rufjected the exchange then will be received a letter to go out of Aamerica after 6 or 1 year.Because right now the USCIS has enough people and time to track illegal people, especially for the people like your wife having the cap.Please call the attoney quickly.Good luck!!!