802.11g High Power 200mW Wireless USB Adapter with Detachable Antenna & SuperG 108Mbps
I'm asking $15.00 for it, shipped anywhere in the Continental US.
The photos don't show the included antenna, but I do have it and will include it, if you want.
If you're considering buying this WiFi adapter, you're not buying it so you can use the original antenna. The external port allows you to connect to any external wifi antenna.
I used it w/ a 7dBi gain magnetic-mount antenna on the roof of my Tacoma and could easily pick up access points a half mile away in a suburban environment.
With true line-of-sight, I've connected to APs well over 3/4 mile away.
Yeah, it' old, but it works, and works damn well.
Downloads (user manual, drivers)