In a command prompt, type in ipconfig. Look for wireless LAN adapter in the result.
Here is an example output. Default Gateway shown is your router.
Wireless LAN adapter Wireless Network Connection:
Connection-specific DNS Suffix . :
IPv4 Address. . . . . . . . . . . : 192.168.101.103
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.101.1