Sounds like you captured/ingested the footage using Final Cut Express ... is that correct?
What version of FCE are you using? And what, exactly, is your HD cam (make & model)?
If you captured/ingested via FCE then you can just copy the clip files wherever you want to. There will be no change in quality. However, if you copied directly from the memory card, that's a different story - knowing the make/model of your camcorder will help there.