A tough question, which only someone who has seen native footage from the Practika and compared it with a similarly-priced standard def camera can answer definitively. As a photographer you no doubt understand that resolution isn't everything, and "Full HD" usually just means 1920x1080 pixels, and is not synonymous with "good optics" or "big sensor" or "high quality image processing."
I'm making an edjumicated guess because I've never seen the Practika let alone compared its output with another camcorder, but I'd say that unless you're willing to spend around £400 or more, you'll not see much improvement over what you're presently using.
Could be wrong though.
Andrew.
EDIT: Google tells me the JVC has a single 1/6" CCD - plenty of room for improvement there. The Practika has a 1/2.5" (I think that means 2/5" but whatever!) CMOS. The numbers suggest that the Practika will be better for shooting indoors. In conjunction with the pixel count this suggests it could well be noticeably sharper than the JVC.