For $5.00, or less, you can pick up RTL 8139 cards all day long on
http://www.eBay.com. RTL 8139 is a chipset made by Realtek, which is probably the most used chipset for NIC's. Most 3com cards will work. You must have just made a mistake and got a rare 3com card that doesn't work. The Netgear FA311 will work. That's the manufacturer and chipset.