Help with vba

How can I edit this so that it will add a prefix to the save as file name. Ex. The save as box opens and in the file name area it has a designated prefix such as "Q-1". Or, after the user saves the file, the "Q-" is added to the begining of the file name.

Sub WkbOpn3()
Dim xFileName As String
MsgBox "Please save a copy of this workbook." & vbNewLine & "You will be prompted to save when you click OK., vbInformation
xFileName = Application.GetSaveAsFilename(, "Excel Macro-Enabled Workbook (*.xlsm), *.xlsm", , "Save As xlsm file")
If xFileName <> "False" Then
Application.EnableEvents = False
ActiveWorkbook.SaveAs Filename:=xFileName, FileFormat:=xlOpenXMLWorkbookMacroEnabled
Application.EnableEvents = True
Else
MsgBox "Action Cancelled"
End If
End Sub

Thank you so much. I thought I tried that, but I guess I missed typed.

Just out of curiosity. Is there a way to edit the macro to automatically add the Q- without user input. Say, after they put in their file name?