I've gone this route before with HP for a client. You can download the printer drivers (they're on the same page you linked). I would recommend the PCL6 drivers.
HOWEVER you CANNOT download the scanner drivers and scanning software. The reason for that is because of the licensing agreement that HP has with the publisher that supplies the scanning software.
You have to order the CD (free, but you eat shipping).
Your best option may be just to post a request on a few of the forums here and see if anyone can copy their CD for you.