This is a relatively advanced topic. From the extension plugin, you have access to the Calling Screen's objects when a button/command is executed from it. So you CAN access that data directly when processing button codes. An example of this method would be (from the ProcessCommand function):
msgbox frm.DL.Path + frm.DL.GetItem(frm.DL.Value)
Add the above and make a button in the audio browser with that code and when pressing it, a messagebox with the path to the item selected will show. You'd have to look at RR's frmSkin's objects and their properties to know what all you can/can't do.. this does not
However, if you wish to access such information on a timer basis, you can request "DLPATH" and "DLTEXT" via SDK's request commands -- this would require you to add a form (even if hidden), to implement the SDK support to receive messages from RR.