Simple log in problem?

Ok the set up I have is simple.
I live above my dad who has Internet.
I have my router hooked to his router via eithernet.
My router is a new belkin n750. Everything works great but heres the problem.
I set my router as access point so I could link up some ip cams and now I can't log into my belkin router. The default ip address doesnt work anymore and I can't find the the belkin router anywhere on the network.

Question
How can I log into the belkin?

No one here can/will help?