Before I start I should state that I am pretty non-knowledgeable when it comes to networking, and most of the terms go right over my head, but I am pretty good at searching for information and how-to's and I'm a fast learner, so any information thrown at me will be useful.

We've recently bought and moved into a new place. We've converted the detached garage into an office space, and when the sparkie was here to wire it up I asked him to add a phone jack into the office because I thought I would put the broadband modem and the mac airport in there. However, we've decided to keep the phone, modem and airport in the lounge since my partner uses the computer in the house most of the timem and most evenings I work in the house too.  Now I want to have a wired and wireless connection in the office as well, but not sure how to go about it. Telecom sent me an extra modem when we moved in as our old contract had expired and we signed up for a new one, but from all the reading I've done I can't really use this new modem as an extender or "repeater".  I also know, from most of my reading, that I can't just plug the new modem in in the office and have it work on my same broadband connection... or can I? All my research says no.  But maybe I'm missing something?

My last thought was to have the sparkie come back in and run an ethernet cable under the house from the lounge into the office, and somehow connect the two modems together so I have wired and wireless in both places. But again, maybe I'm talking out of my a#$.  

Any suggestions are welcome :)

thanks