Tempatures for Bearded Dragons

Question
I've inherited a male & female bearded dragons.  We have them in a large cage outside in my backyard.  We live in Los Angeles and the temputures are dipping into the low 40's a night.  I have them under a two heat lamps but they do not seem warm enough.  I was going to buy a floor heater thingy today.  I'm worried that they are going to be to cold at night.  I've noticed the female has no energy today at all and hasn't been eating.  I love these little guys and want to take care of them.  Please help as I will be crushed if they die, especially my little girls who have grown to love them a lot.

Answer
Hello Michael,
First off, keeping a male & a female together wont work out long term.  Unless you want to breed, the male will breed her way too much & can overbreed her & cause health problems.  How large is the outdoor tank?
Yes, that is too cold.  You will need to move them in with weather like that if they don't have enough cover.  Just put them in a blankie & get a plastic bin to put them in at night so they will stay warm overnight, then you can move them outside the next day.  
They do brumate in the wintertime though, which is normal.  However, they do need shelter to keep out of the elements as well.
How old are they?

Tracie