How to accesss router from another router/modem

Hey
does anybody knows, how to access router ip from modem connected computer????
I am successfully accessing modem from router connected device but not reverse::frowning:
On searching on google i came across below link, but as solution given, there is no such NAT options in my iball WRX150N router... My connections are same like given there. Modem IP is 192.168.1.1 and the router ip is 192.168.2.1
Don't know how to do it?
Link: networking - Accessing router from another router/modem - Super User

What mode is your WRX150N running?

(Its more likely that you will get answers to this problem on superuser.com than here in the arduino forums..)

My WRX150N is in 'ROUTER' mode.

(i don't know concept of of these modes but i also tried 'BRIDGE' mode)