Detect IP range of the Wifi network?!

Here is my situation:

- The Wifi network I try to access is using WPA-PSK and I've already found out that key.
- However, the router's DHCP is disabled, and I do not know its IP Range, as well as its subnet mask and default gateway.

Therefore, I cannot connect to that Wireless network.

Is there any way/tools to detect the IP Range of the network from the outside ?! My friend told me that I can use some tool like Wireshark to sniff packet and find out that IP range, but how can I sniff when I cannot connect to it ?!

Is there any tool in Backtrack that can help me to do it ?! If yes, please guide me a little bit on how to use it since I'm not an expert in using Linux.

Thanks all of you a lot :)

I believe that Kismet will fit your needs (as long as your wireless card will go into monitor mode). Look for it under the WLAN section of BackTrack. If there is traffic on the LAN between a client & the router, Kismet should tell you the IP range.

Yes this is believable.
Leave networks that you are not directly authorized to use alone.