Retrieving Approved By & Approved Date

Using the Purchasing function within ServiceDesk. After the PO approver marks the PO as approved it stamps the date and that person's Active Directory name on the purchase order form. That feature is TERRIFIC however, when the PO is closed the status changes to close and the Approved by and Approved Date are no longer visible on the PO form. Is there a way to retrieve this information? We linked it to AD for auditing purposes but it doesn't do us any good if the information is not retrievable. I can't find the fields in report builder to even build a report that would list something like PO #, Approved by, Approved Date.

HELP!!