Question on wattage

Hello all - this is my first post, after having grown peppers for the past 5 years. I've decided to try to overwinter some of my plants this year, and had a question about lighting.
I have a Sun Systems lamp, with a 400 watt metal halide bulb, that I bought a few years back for starting plants indoors. However, my plants seemed to do very poorly with this - I'm not sure if the issue was the lighting or if I was doing something else wrong. 
I now have a few dozen healthy plants, but am in upstate New York, so the growing season will soon come to an end, and I was planning on bringing six or eight inside. Might the 400 watt bulb be too bright for these? Should I try a 250 w bulb? Or does it seem that the previous plants fared poorly from being too young for the grow light?
Any thoughts or suggestions would be very much appreciated.
Ammon

how big are the plants? Might want to save yourself some coin and use compact florescent lighting during the winter. 

They're about 3 feet tall. I'm not terribly worried about electrical cost, and the lamp I have is already set up so I'd prefer working with if, if there's a way of doing so.
Thanks.

you can do like a 6x6 area with the 400, should get them thru the winter, as far as any stunted growth, probably best to post some pic, so folks can advise.
 
also forgot to mention bringing in fresh air (via fan) across the plants, removes the excess heat from the MH, and helps the plants out as well.

Too bright shouldn't be an issue. MH bulbs are notorious for heat generation.
Maybe temps were too hot the first time you tried it?
 

My guess is that my fan set-up wasn't as effective as it should have been. I'll try the 400w again, and with better ventilation.
Thanks all.

Depends on what you want to accomplish.  Generally, wintering over is to keep the root system alive.  People will trim them suckers way down so the plant has much less requirement for light.  Here is the problem you will run into with MH and three foot plants.  Artificial light doesn't penetrate the canopy very well and if you get them too close, they burn leaves.  The only way I have found to grow tall plants under MH is with supplemental side lights.  Used to be 4 foot tubes on the wall.  Then compact florescent up between plants.

If you have a long cord between the ballast and the bulb then put one in one room and the other in the other.  Both produce heat, so spread them out.  Keeping that ballast away from the water is a good thing anyway.  If it is winter, dont bother venting that heat outide.  Let it help heat your house.  In fact, since you are not growing anything illegal why not grow out in the open.  If you do it in the living room, well you dont have to worry about lighting the living room.  Maybe put curtains around the grow area.

To see what I mean about sidelights, search a cannibals site for the term palm tree.  When what you are after is a single top bud, it is not a problem.  With pepper plants, it is a problem.

The 400w MH lamp should be putting out about 25000 lumens after some use.
 
You need 3000 lumens per square foot of plant canopy to get fruit.