Resiliant internet connection?

[Poker monkey]

Just wondering if anyone has advice (or can point me to a topic) which shows me how to set up a reliable internet connection.

Currently I have 6 Mbps broadband, going through a wireless Netgear DG834G router, which I share with two flatmates. The problem is that if one of my flatmates is making heavy use of the connection (downloading a large file / movie etc), it slows down massively for me, to such an extent that there big delays, I lose my connection to the poker site, get kicked off the table if I'm playing Ongame etc.

Is there any device or router that will stop any one user using over 90% of the bandwidth at a time?

Also, is there any "home" solution for connecting to multiple internet service providers in case my service provider temporarily has a problem?