Adding an image question

I am trying to add a label on a clothing . it has its own texture.  If there is a seperate mesh for the label on my 3D Model   then  it places with it is own texture on that mesh, but if there is not a seperate mesh then the image that i add  takes the background texture.

As an example  lets say the clothing has ribbing texture.  if i am adding an image on it, it works like stamping  and takes that ribbing texture. Is there a way adding an image with it is on texture when there isnt seperate mesh for it? 

I tried masking it but  it didint work because it is a polygon masking so  i couldnt select an area on the clothing  with a perfect square to add the label in it.

Is there a way to solve this issue?

Thanks!!