My house is cold, too. I have an IPA now sitting at 61 degrees.
There are a couple of things that help. One is, you can buy a yeast (like nottingham) that works down to 57-59 degrees. Keep the fermenter off the basement floor (where it's coldest) by putting it up on a shelf, or put boards underneath. If you have an ale that you must ferment a little warmer, then you can do what I've done in the past- I put the fermenter in a cooler with a water bath, and add a $10 aquarium heater to the water. I ferment at 70 degrees or so that way. You have to keep an eye on it (I use a floating thermometer in the water bath, as well as a stick on thermometer just above the water level on the fermener) to make sure it doesn't get too warm, but it works great.