Its difficult to help because I can't see what you can see. However, you don't need a new router nor a more powerful one. I have not found that many broken out of the box not have I found them difficult to install.
May I suggest that your reinstall it following the instructions that came with it - to the letter! In addition ensure that the TCP/IP settings for your Ethernet (I'm guessing Ethernet because you don't say what you are using.) adapters on each PC are set for DHCP.
T
October 2008