USB 2.0

I have an AMD Athlon 1.1 GHz with 512 MB RAM AND winxp OS.I HAVE SEVERAL usb 1.0 ports. I want to buy a USB 2.0 EXTERNAL HARD DRIVE which will work on my USB 1.0 PORTS BUT THE SPEED OF a usb 2.0 is much better. I have several PCI Slots available. Can I make these compatabilie with an adapter card which will give me USB 2.0 ports from the card?Thanks.