Identify Wireless MAC Address

You are right. Your W-LAN "HWAddr" (Hardware Address) is your wireless devices MAC Address. You can look it up by typing

ifconfig wlan0

which will show you something like this

wlan0     Link encap:Ethernet  Hardware Adresse 00:c0:ca:19:d3:1e
          UP BROADCAST MULTICAST  MTU:1500  Metrik:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:1000 
          RX-Bytes:0 (0.0 B)  TX-Bytes:0 (0.0 B)

In case your wireless adapter uses another interface name, which you do not know, do the following:

• Use ifconfig to get a listing of all interfaces
• Disconnect the USB-Device
• Check which one is missing, by reissuing ifconfig

The wlan0 HWaddr reported by the command ifconfig actually is the correct MAC address. It looks like this :

 HWaddr 51:04:b6:07:42:73

So either the MAC filtering was incorrectly set up, or you have other interfaces or options (you did not post ifconfig output so it is rather hard to guess).

Do try another wifi access point, just to check the ability to connect to network without other problems.