Not all light boxes are the same. I'd do some research, starting with anything written by Norman Rosenthal (he's got a great book on SAD that you can get through your library).
This is my light box: http://www.alaskanorthernlights.com/
It's not the cheapest one out there but it is medical grade and has lasted me eight years so far. Beginning in October I put it on my computer desk and turn it on in the morning while I surf the web.
I believe the standard advice is to use it for 1/2 an hour each morning but by January I've got it on from 8:00am to Noon.Laohaire
, I totally understand what you mean about dreading autumn. I'm the same way and it's a shame because autumn is such a beautiful season.
I think that getting lots of sunshine in the summer is great for helping mood stability in the summer. But unfortunately it does not seem possible to store it up for the winter.
Just like winter trips somewhere sunny... it's great for while you are there but it doesn't last once you return home. My friend once asked me if my February trips eliminate SAD. I said that it does wonders during February! But once I'm back north in cold and gray Michigan, my March sucks.
This fall/winter I'm going to try to spend some time outdoors every day but man, that goes against every instinct I have!