They do make them.
I have seen them at Home Depot or Lowe's (can you tell I spend just a little time in these Home centers???) I can't remember. It is basically a remote for the thermostat. I didnt't bother with one because I thought the placement of the thermostats in my house wouldn't lend well to a remote but yours might.
You will have to replace the thermostat though with this model it is not an add on to your ucrrent one.