How To Determine Wireless Router IP

Hi,
Here's the problem I'm facing. My home network previous used a wired router to provide connectivity to different computers at home. My dad got a wireless router installed which is basically now connected to the wired router - which has an ip address of 192.168.1.1. The wired router still serves as the DHCP server too - so that any computer that gets on the network either wired or wireless has the wired router assign it an ip address.
Now the problem I'm facing is that the wireless router assigns ip addresses to some laptops, in order to troubleshoot this i need to get get access to the wireless router, now I can;t disrupt the network at home so i cant reset the ip address of the wireless router which is a TP-LINK. Now since I didn't setup this router (the wireless one) I don't know what the ip address is - of course neither does my dad. The question now is how can I get the ip address - Even if I connect my laptop directly to the wireless router without the ip address i'm unsure how to proceed. It certainily isnt 192.168.1.1 - as that is the wired router. Even if i login to a laptop that can connect to the wirless network and issue and ipconfig /all, the default gateway is shown as 192.168.1.1 - which again is the wired router. I've tried wireshark but i'm not too good with figuring anything out with that. Appreciate any help I can get here. thanks

download NETSCAN
run netscan