Greening Your Home - Combination of light sensitive switch and timer

Hi, I'm looking for something that I think may not exist, but hoping someone here might know the solution for what I'm trying to do. My home has 2 lamp posts along the front walkway to my front door. The previous owner had it installed, but wired it in a way that it was plugged into a timer. Probably not the best way to do it, but he used outdoor-safe extension cords (not sure what you call them, but I was told it was safe), and the timer is plugged in. The first thing I did was change the bulbs to CF ones. The timer is great because it allows me to have the lamps turn off around 11pm. But the hassle for me is that I have to adjust the starting time as sunset changes throughout the year. I'd like to have it so that they just turn on when it gets dark, but cut out when it reaches a certain time. Is there such a combination of a light-sensitive switch with a timer?

Here is what I have done with my driveway lights and yard lights that is very similar. All of my circuits are 120 volt AC. I use a 24 hr timer to control the ac voltage to the circuit and a 120volt photo cell to control the on time of the lights. The timer will turn the circuit on and off at what ever time I want and the photo cell will allow the lights to come on when it gets dark enough for the lights and the timer will turn them off any anytime I set it at.