The easiest way to test this would be to unplug your modem and just plug in the power at the new modem location you're planning. From there you can check on your devices around the house if you're getting the WiFi signal. You won't be able to use the internet at that point, but you'll be able to see if the signal is reaching the places you want it to.
From there, we can arrange a Chorus technician to come out and install another jackpoint if you want to go ahead, but there would be a charge invloved. It would probably be a lot cheaper to get a local electrician to come and do it.
Alternatively, you could look at getting a WiFi Range Extender/Booster which you just plug into power and setup in a few minutes.
I work for Vodafone, supporting our mobile and fixed customers, and volunteer my time on the community.
PM = Private Message. Click on my name to send me a message.