Pak0.pak can be downloaded as shareware, but you'll need the Quake CD to get pak1.pak. Of course there are other ways to get the full game, but we can't really talk about that here.
If you do have the Quake CD already, install the game on your PC and copy the files from your quake folder to your SD using a card reader. Installing it on XP is kinda tricky, though...tell me if you have probs.