VOIP OVER WIRELESS

Hi People!

I have a question.... upstairs in my house (which is victorian so has
thick walls) is a Buffalo Wireless Broad Band Router wich is connected
to ntl broadband which is loacted upstairs (the kind people at ntl will
install anywhere in your house for free The signal is then
transmitted through-out the house

What i want to do:

I want to connect a VOIP adaptor downstairs

The Problem :

My broadband connection is upstairs, however it is transmitted around
the house wirelessly

My suggestion:

Would it be possible for me to place an AP downstairs and connect the
VOIP adaptor to it? And if so would i need to set it up in repeater mode?

Please Help

I need my Free Phone Calls!

Thanks

"ANY" help appreciated

Gavin