hi there
I'll be very thankful if anyone can help me with inserting a company logo (or any predefined data) in Standard templates (i.e. A1, A2, A3,... paper sizes) .
Is there any method or Autolisp code I can use?

Just use standard AutoCAD commands to modify your templates - and save the drawing back to the DWT format (or save a DWG and rename it to DWT).