You can always use a lamp to provide heat to the kit, and if you want total control, you can use a heat controller (I dont know the name in english, but it's that thing that control the temperature, and can turn on and off the power supply of a heat source, depending on the temperature that you set it to mantain. I'm being clear enought? Well, all refrigirators, heaters, ovens have it.)
This way you can "program" that device for switch on the light when the temperature gets to low, and to turn off when the temperature is above the right temperature.
Any "normal" light will produce heat, so this way you can have light and heat, from the same source, without using direct sunlight.
When using a tupperware container, you can use it's cover. You should keep it a little open, so the air can move.
Using this technic, I think you can put the kit anywere.