Measurement of Quiescent Current and Operating Current in Gate driver
I am measuring Quiescent current at 1 (VSS) for now from below figure, Or should I consider current at 2 (RT1 and RT2) so that it comes to Quiescent current= Current at 1 + Current at 2 ?


Carefully look at the subscripts of the parameters (underlined in red):  

   

The current \$ I_{DD}\$ is the current that enters the \$ V_{DD}\$ pin and is therefore called "\$ V_{DD}\$ Quiescent current". So, you should measure this current at the \$ V_{DD}\$ pin.  


  Where should i measure operating current providing f=500KHz input?  


Same as above, at the \$ V_{DD}\$ pin


  This table gives operating current for 25 degree as 1.5mA
  When I relate this to below plot which is w.r.t to temperature the operating current contradicts the table value.


Note that the table specifies a typical value. I would also expect this typical value in Figure 2, but probably they used a different measurement setup, yielding a different operating current than the typical value. (Note the same applies to \$I_{HBO}\$.)
It is not uncommon to find such a (seemingly) "inconsistency" in datasheets.