Problem Using Router + Modem

I recently replaced my modem with a new one, but I've been having problems connecting from a room upstairs with my laptop and Xbox Live because the wifi signal is so weak. Everything is fine otherwise. The modem is connected to the cable and not the phone line. I thought I could buy a separate router with a stronger wifi signal, hook it up to the modem via an ethernet cable and use that for wireless networking instead. I set everything up amy computer says I'm connected to the internet, and the router shows up as a wireless network on my laptop...however I can't actually access the internet from it, either on the desktop computer or from my laptop. I realize this is likely a very simple problem with a simple solution, but I'm a novice at actually maintaining my computer so I have no idea what could be wrong or where to begin with fixing it. Can anyone help or give me some suggestions?

 

Hi Trahison.Welcome to Computer Help Forums.
I know modem signal boosters are available, having never used one can't vouch for them.

 

What is the Model number and make of both the computer and the router? Have you tried any other wireless devices using that router?

 

Hi, thanks for the responses. My computer is a Gateway DX4820. My modem is a Motorola SBG6580 and the new router is a D-link DIR601.

Both my ipod and my Xbox, as well as my laptop, recognize the D-link as a wireless network and allow me to connect to it, but I can't actually surf the internet or use any online functions with either. The desktop computer directly connected to the modem & router also claimed to be connected to the internet, but I couldn't use it. I was forced to disconnect the router and continue using just my modem with the weak wifi. I've thought about purchasing a wifi extender but I was hoping this would work instead.