Are you sure the device that you plug in to the USB 2.0 port, is a USB 2.0 device? You will not get USB 2.0 speeds to a USB 1.1 device, and your PC Card may only have a single bus connection to both ports. So, if you connect two devices, and one is not USB 2.0, then both will downgrade automatically. This is not a problem with the card, or the drivers. Connect just one device that you are certain is USB 2.0, and check the USB tab in System Profiler. You will likely see USB 2.0 (hi-speed) with that setup.
Serendipity is a lucky guess !