I have two wireless modem routers at my house. Can I use the extra one as a signal amplifier for the other?
you can enable one router to act a wireless bridge. but check if your router supports the same.
AFAIK, every router supports bridge mode.
Yes, you can use it as repeater. You just need to set it up.
Teracom Type II ADSL 2+ CPE/IAD.
How to set it up? The routers are D-Link DSL-2750U and Teracom Type II ADSL 2+ CPE/IAD.
I am pretty sure both support wireless bridge.