Just some information that I thought would be helpful in why you might be having this problem
A router's main function is to separate networks
It complicates things when you have two router's, and two different networks, when you don't really need it.
What do you need to extend in your network, wireless or wired connections? (The reason I ask is that there are better devices, to help extend your network besides routers if interested let me know)
Can a PC have 2 different ip numbers?
To answer your question No, In theory you can but you need to have two NIC cards, such as an wireless and wired connection would work (I say theory because I personally have never tried but I don't see why it would not work?)
But back to the problem, Are you able to ping the router on the 192.168.1.x network?
If so my guess is that a routing protocol needs to be used on both of the of the routers in order to get the login screen of the other router. (Since they are on different networks they need to know about each other)
If you can't find your manual I looked it up and this is what I found for the router you specified SMC Networks - SUPPORT EN_USA
Now I don't know if your router has this function, but look for something like routing protocol, or RIP version 1 or RIP version 2 or even Dynamic Routing...
You may have to just plug a PC to that router and nothing else to access it, to see if you can find the above settings.
Hope the above information helps,