Hi Sridhar,
In OOPS world you have to use Event handler for class "cl_gui_alv_grid" and event name is "print_top_of_page".
Please go through the detailed explanation with usage of top of page in ALV OOPS.
http://wiki.scn.sap.com/wiki/pages/viewpage.action?pageId=37564
Hope it will be helpful.
Regards,
Kannan