Aniket, I think Subrat wants the coordinates of the isoline of stress. I haven't tried your suggestion, but expect that is not what is output.

Subrat, I would use a digitizing program (inside matlab, I use Grabit) and manually click on the isoline. If you change the plot style from filled to Isoline, you can have an actual line, and you can reduce the number of bands to just a few and if you turn off element edges, those will not interfere with the digitizing. You can use symmetry and digitize only to the top half.

You should also reduce your mesh size as I expect the isoline will move a little as the elements get smaller. I can see some mesh dependence in the isoline with the current element size.