How best to WIFI a iMac (CRT)?

Okay folks, here's the deal: I've just installed a 2Wire Gateway wireless hub at my PC and want to get my wife's iMac on the WIFI network. I'd be grateful for any advice you good people could offer.

The computer in question is one of the old CRT Ruby iMac DV's (summer 2000) with a CD option instead of the DVD drive. The OS is still the original that came with it, OS 9.1x I believe. It has an AirPort port, but we never bought an AirPort card for it. The iMac is upstairs, and the PC/WIFI hub downstairs, approximately 30 feet away, horizontally speaking. The house is wood frame.

So, what is my best course of action? Should I pick up an old AirPort card off of eBay? I've heard that those AirPort cards have very limited range, so will this be an issue? Is it worth it to look into any USB devices? Will I need to upgrad to OS X? I'm under the impression that this will be a significant hassle for an older iMac. Buying a new iMac isn't an option right now, as the current one is more than adequate for the limited uses we have for it.

Thanks in advance!

the best thing I would say you should do it look for a Ethernet to Wireless adaptor. Its an external box that acts as a wireless receiver and converts the signal to the ethernet port. the box is setup to use DHCP, and i think it is configurable through a web interface if needed. But I bought a few of these for a client and they just plugged in and the imacs were wireless. No drivers or anything to worry about.