Hi Durga,
You can use class CL_SALV_BS_RUNTIME_INFO too access ALV data.
In thid blog you can find explanation : http://scn.sap.com/community/abap/blog/2011/07/07/gain-programmatic-access-to-data-of-sapgui-alv-reports
this is usefull trick and thanks to Glen Simpson for sharing this.
Regards