I managed to get the enhanced controller installed.
I went to usbman website and found a usb tips and tricks page for the
SiS 7001 host controller.
When i changed some settings in the BIOS listed in the website, I got a "Windows was not shutdown properly" message. I tried the start windows normally option but I got the same message.
I started windows in safemode and uninstalled the USB Root Hubs and Host controllers.
When I restarted I went and reset all my BIOS settings. The computer started ok and the Enhanced controller is listed in the device manager.
The device driver file version is microsoft 5.1.2600.2180 xpsp_sp2_rtm 040803_2158.
I'm thinking I probably didnt need to mess with my BIOS settings in the first place; just installing the patch in safemode might have fixed it.