Router to router

I need some advice about a home network I am trying to set up. I will be moving to BT business broadband very soon and will be getting a business wireless hub.
I already have a linksys router which I have in my lounge downstairs. This connects to 2 games consoles (one wired and one wireless) in that room. In the office upstairs, I have 3 computers connecting wirelessly to the Linksys router (this signal can range between 1-4 bars of a possible 5 depending on the time of day)

I wanted to know if it is possible for me to put the BT wireless hub in the office upstairs to use it as a repeater so that i can then use VoIP by plugging a phone in it and to connect the laptops to that router wirelessly in my office, while leaving the linksys downstairs. So effectively the linksys will send the signal to the BT router and this will then give signal to a phone and 3 laptops.

Thanks in advance