Imager is correct but you can correct this light inconsistency to an acceptable level in 2 stages.

First stage is to try and even out the light levels in the wings layer:

1. Select the wings layer, add a new level adjustment layer and then create a clipping mask to confine the level adjustments to just the wings layer.
2. Add a layer mask to the levels layer and then go to the channels tab of this layer and select the levels layer mask.
3. Select your gradient tool with a radial gradient black to white.
4. Now create your radial gradient with the starting point (first mouse click) on the brightest spot of the wings layer and the end point (second moue click) where the light levels even out.
5. Play around with the levels sliders to get as even light distribution as you can.  Don't worry if the wings layer is washed out. When your happy with the result merge these three layers.
6. Now add a second level adjustment layer (repeating step 1) above the first and adjust the sliders to bring back the colour and contrast. 

Once this is done the next stage is to add the new light source.

1. Goto Filter>Render>Lighting Effects
2. Leave the Style at Default then choose Omni as the light type
3. In your preview window move the light source to where the light source in your character render is.
4. Adjust the outer ring to spread the light and adjust the Intensity slider to adjust the strength of the omni light.
5. If your not happy with the new light source go back and try different preset styles for the lighting effect until you find one that your happy with.

Since my post above addressing the shadow creation I have tested the method in the second paragraph out and it works well.  The only addition I would make is that you should assign an off white colour (or a colour that matches the wings) to the box in Poser for your shadow pattern.

Shane

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