The further away from the wireless router you are the slower the connection is but you don't notice it on Internet Traffic but when doing PC to PC transfer of data it is noticable, I run CAT5 when doing data transfer. If you have a Panasonic 2.4Ghz Cordless Telephone it may interfer with the wireless when using the hand piece close to either the router or wireless PC.
You would need I think cable or ADSL for wireless Internet as I couldn't find a router that does dial up not attaches the external dial up modem to it...