See http://www.macwireless.com/ for possible upgrade cards. http://support.apple.com/kb/HT1621 says at least the Quicksilver models all used the original airport card which is only 802.11b and at best WPA1 compatible, but not WPA2 compatible. WEP is not even worth considering. Your 1.33 Ghz Powerbook is compatible with the 802.11g Airport Extreme card, and WPA2. Built-in it can't be upgraded to 802.11n.
For the QS, there are three ways to get wireless "n"
1) Install a USB2.0 PCI adaptor card AND use this dongle:
I asked the vendor if that would enable "n" speeds if attached to a 2.0 port on a PCI cardand they said yes. Without the PCI adaptor card, this deveice gives only "b" on a USB 1.1 port.
2) Install a PCI wireless adaptor:
3) Use a wireless brigde:
Not portable but would also work on the PB when not mobile
If your PowerBook has USB 2.0 (it should if you're inquiring about the 12" 1.33G in your profile) the dongle would work at "n" speed without any extra hardware. That makes option 1 the most cost-effective if you want to get both computers to "n"
Thanks a brody for the suggestions. I looked at the possible upgrade cards available on macwireless.com and I'm thinking I might go the usb wi-fi adapter route for now. Unfortunately, I don't have it in the budget to spend as much on a card and I think the security options and versatility of the usb adapter have me leaning that direction. Your feedback is really appreciated though.