Got the clips and all is good. Windows is held firmly and now open and close without any problem!
Since this was the first window regulator job for me, I had not idea what the clip looks like originally. So I was trying to get the windows hold without any success and then realized it must have been broken.
Here's the broken clip on the right:
and the new one on the left:
Also, I looks like the reason for these parts to fail so frequently, might have to do with slamming the door closed while the window is at full open. When the window is at down position, the carrier clips vibrates further distance when the door is being closed, causing the plastic part of the clips to break.
As always, thanks for the great help from this forum!