Trying to setup additional router as repeater...

I have an old Ambit router/modem combo that I received through Time Warner. The connection is almost always awful, and just a mess in general -- constantly having to unplug it and then plug it back in to get certain things to connect, and the such.

Yesterday, I bought a Belkin N300 router to setup as a repeater. I plugged it in to the router/modem I have now, and then plugged it into my computer. I clicked on the option that said "use this as an access point", and I think that may have messed things up.

Currently, I can connect to the new Belkin router. However... I wanted to use it as just a repeater. Also, I think the IP address of it somehow got changed, because "192.168.2.1" no longer connects no matter what, even though it did the first time.

I tried resetting and using the installation disc that came with it, but no dice. So, my questions:

1. Did the IP address change? And if so, how can I find it so I can connect to the settings? (IP for Ambit router is 192.168.0.1 -- I can connect to that one fine. Just not the Belkin. Tried going into CMD then typing ipconfig, but the only thing that pops up is for my Ambit router.

2. How do I go about using this router as a repeater?