Here is a stripped down version of your vbs script, converted into a kix function. Just copy the function to your existing kix script, and you can call the function at any time using the card number you want, and the computer you want. I didn't write in any error checking, so you may want to test it out a bit beforehand. But should get you started.

 Code:
$bssid = GetBSSID(1,@Wksta)

$null = MessageBox($bssid,"BSSID",0)

FUNCTION GetBSSID($device, optional $machine)
   $strComputer = IIF (VarType($machine)<2, @Wksta, $Machine)

   $objSWbemServices = GetObject("winmgmts:\\"+ $strComputer + "\root\wmi")
   $colInstances = $objSwbemServices.ExecQuery("SELECT * FROM MSNdis_80211_ReceivedSignalStrength WHERE Active=True")

   $card_no=$device
   $x=1
   for each $objInstance in $colInstances
      if $x = $card_no
         $wifiAdapter = $objInstance.InstanceName
         $x = $x + 1
      endif
   next
   $last_signal = 0
   $bssid = ""
   $colInstances = $objSwbemServices.ExecQuery('SELECT * FROM MSNdis_80211_BaseServiceSetIdentifier WHERE Active = True AND InstanceName ="'+$wifiAdapter+'"')
   for each $objInstance in $colInstances
      $macbyte = 0
      for each $decval in $objInstance.Ndis80211MacAddress
         if $decval<17
            $bssid = $bssid + "0"
         endif
         $bssid = $bssid + DecToHex($decval)
         if $macbyte < 5
            $bssid = $bssid + ":"
            $macbyte = $macbyte + 1
         endif
      next
   next
   $colInstances = $objSwbemServices.ExecQuery ("SELECT * FROM MSNdis_80211_ReceivedSignalStrength WHERE Active = True AND InstanceName ='" + $wifiAdapter + "'")
   for each $objInstance in $colInstances
      $sigraw = $objInstance.Ndis80211ReceivedSignalStrength
      $signal = $sigraw + "dB"
   next
   $last_signal = $sigraw
   $GetBSSID = $bssid
ENDFUNCTION