First let me say I am no techie so excuse my wrong termilogy

I had a netvigator wifi modem on my ground floor that was emitting an acceptable signal for my bedroom on the 1st floor. It broke down and PCCW changed it (looks exactly the same) but now the signal can no longer be received upstairs in my bedroom.

1) Are they any routers that can do a better job? Will it work by changing to a different router i.e Netvigator or 3rd party router like linksys?
2) I have a NowTV connection in my bedroom which means I have a modem there. Can I plug another router in the modem to get a wifi signal?

Basically, I want to be able to use my notebook in my bedroom as well as living room. Any suggestions at all appreciated. Thanks in advance