Adaptec and a number of other vendors offer pcmcia cards that support USB2 and or Firewire for laptops that don't have support for those ports built in. One word of caution if you are planning on attaching a device that is depending on the USB port to supply it's power many of these adapters will be unable to provide an adequate level of power for things like external HDs. Some of the adapters allow you to plug an external power supply into them so they can power such device OK sitting at a desk but not so great away from the AC power. I found out about the power issue when I tried to take my old laptop HD put it in an external USB2.0 case and use it with the Adaptec adapter. At first I thought the adapter was defective. The exteral HD encloser worked fine with a desktop system but not with the notebook. More reading revealed the power issue. Since the item you want to connect is a scanner that low power shouldn't be an issue for you, the scanner has it's own power supply. One last word of warning if you also use a PCMCIA wireless adapter you won't be able to use both the NIC and the USB adapter at the same time.
Good luck