Transparent Background proving difficult

Make a duplicate layer and use threshold to make it solid black and to remove the jpg artifacts on that layer. 

Use the Blend if slider in layer options to remove the (now solid) white area

With the orginal logo on top, option-click between the layers 

This effectively makes the solid-black-and-transparent layer into a mask for the original layer.

If you cannot get the vestor data you could 

• Load the Channel with the best separation as a selection (ctrl-click the Channel’s icon in the Channels Panel)

• Select > Inverse 

• Layer > New Fill Layer > Solid Color 

• alt-click the Layer Mask-icon in the Layers Panel and apply a Curves Adjustment to increase the contrast

• Hide the Background Layer