If you haven't already, make a copy of the character layer and then blur it using Gaussian Blur to 2 or 3 pixels. Get the eraser and set it soft round at about 30 px and erase in a bowl like shape around the bottom of the character. An easy way to help it blend with the background a little more.
I noticed the model looks a little blurry around the face as well.
Make sure your Display Mode on WMV is set to this:
It improves the quality of the model a fair bit. Also when you take the screenshot on WMV make sure the you're as zoomed in as possible without cutting parts of the model off that you want in the picture. It will look better when you scale it down.
You can also get an image filter like Topaz Clean 3 and play around with that for some nice effects.
Besides that it looks nice.