Does a normal wireless router extend Wi-Fi range? About routers?

Basically, I'm in a military camp where they are offering Wi-Fi camp wide. But in my room I only get 2 bars on my laptop when standing near a certain window as the modem is in another room. My iphone doesn't even see this connection.So, if I fix a wireless router at my place, will I get better signal on my laptop or maybe my iphone will see and connect to it? Wha are the stuff /info that I'll need to setup a router? I only know the Wi-Fi password.

You don't get Wi-Fi from your modem. You have to hook a router to your modem with an Ethernet cable. Then you access the Wi-Fi signal from the router from your laptop. You also can hook your laptop to the modem the Ethernet cable.