Don't use PMB.
2) Your clips are getting much more compressed.
3) Any camcorder will do - including the one you are using, assuming there is enough light. Don't use PMB. Video editors like Sony Vegas can import AVCHD video edit in high definition and export as less compressed video (resulting in larger file size and improved video quality).
WMV is a file type - an envelope - that can contain different kinds of video at different compression rates. It is not so much a WMV issue as it is an issue of the video file inside that WMV envelope.
If you are in the market for a new camcorder "that won't be lose quality when I convert to WMV", you should actually be looking into better software and computer, too... As camcorders increase in price, the lenses and imaging chips get larger and more features (like a mic jack and various manual controls) appear. And the amount of compression applied to the video starts to go down. Your camcorder captures very compressed video - we don't know what you are comparing against, or what editing tools they are using or what compression is used when the file is rendered and prepared for uploading. My 3 minute: 15 second high quality 1080 high definition videos I upload to YouTube are about 1 gig.