will have to look for an extension cable I think, trouble is it’ll need to be able to handle 3 amps.
I found this: http://www.ebay.com.au/itm/3m-DC-3-5mm-1-35mm-Power-Extension-Cable-For-CCTV-Security-IP-Cameras-/222530991989?_trksid=p2141725.m3641.l6368 Do you think it won’t handle 3A?
Yes that should handle 3A, you want 20AWG minimum, which you’ll get 0.1V drop per meter, so that 3m cable would lose 0.3V off the 12V output, hopefully the drop shouldn’t be too much problem for laptop, wouldn’t want a bigger drop than that though.
I just measured the output voltage at the end of the cable of the power supply they come with and its 12.21V, so theoretically you’ll get about 11.9V out of the end of the cable with that 3m extension, for total cable length of ~4m including the 1m built into the power supply.
Or you could get get a whole new power supply, the thing with those brick ones though is that if you’re sitting at a table for example the brick part is always in the middle and ends up having to either hang in mid air and pull the end of the cable unless you stick something heavy on it so it doesn’t move.
Might try look for a extension cable with right angled end