Vista drivers were never written nor released.

This link gets you several discussions about it -
http://www.google.com/search?sourceid=navclient&aq=hts&oq=&ie=UTF-8&rlz=1T4GGLL_enUS310US311&q=BWU613SB

Driverguide.com does have the driver for the BWU613B that is claimed to support the following -

BWU613B
Blitzz Technology Inc.
Network Devices

Win 95, Win 98, Win 98SE, Win ME, Win NT 4.0, Win 2000 Workstation, Win 2000 Server, Win XP Home, Win XP Pro, Win 2003 Server, Win Vista, Win Vista x64, Linux, MacOS, MacOSX
Version 2.9.8.345
FCCID: Q8NAWU2000B


Submitted Jul 30, 2006 by Kheila: "This one actually works! I tried the other ones available here, and couldn't get any to work. This ZIP file seems to... (more)This one actually works! I tried the other ones available here, and couldn't get any to work. This ZIP file seems to contain the contents of the original installation CD, including Mac, Linux, and Windows versions. Just click on the Autorun icon, and follow the instructions. For a Windows installation, you may have to locate the ainu58x file manually, it's located in the Drivers folder."


You would have to give it a try yourself. It is easily located by following this link and performing a search for BLITZZ then scrolling through the search results - http://www.driverguide.com

Personally though I would spend the few bucks to get a new wireless card that has Vista support. There are several cheap ones that work great in Vista and come with the drivers such as:
Rosewill RNX-G300LX IEEE 802.11b/g PCI Wireless Card Up to 54Mbps
and this one too:
Rosewill RNX-G300EX IEEE 802.11b/g PCI Wireless Card Up to 54Mbps