I got a very nice PCMCIA (PC Card) .11N adapter for like $10, actually a couple of them off ebay, and they work nicely. They are very generic no-name brand, but they work and they were a great price.
The one odd thing with them is that only connect up to 270Mbps in .11N mode, (or thats what they report), which is plenty fast enough, but its odd....
I'm checking into this now. My laptop has the below. Is this the same as a PCMCIA card?
Expand Memory and Multimedia Through the ExpressCard Slot
The built-in ExpressCard slot on this laptop lets you easily expand the memory, wireless communications, multimedia, or security of the system. There are two types of ExpressCards: the ExpressCard/34, which measures 34mm by 75mm and is shaped like a stick of chewing gum, and the wider ExpressCard/54, which is 54mm by 75mm. The ExpressCard/54 slot, which accepts either type of card, opens up a wider world of expandability, including SmartCard readers, CompactFlash readers, and 1.8-inch disk drives. Few new laptops come equipped with the old PC Card slot that preceded ExpressCard, but if yours does, you can buy an adapter that lets you use ExpressCards in the PC Card slot.