Gerbera - what's up with mine?

A few weeks ago I bought a couple of Gerbera plants and have them indoors.

They looked great when I bought them, lovely, well formed, vibrant flowers, but now they are starting to look a little crestfallen. The leaves are fine but the flowers, even the newly opened ones, look ragged and pale. A number of buds are still coming on.

What am I doing wrong? Naturally they are kept watered (not too much though).

They are in an east facing window. Temperature isn't too high, maybe varies between about 18 to 23 celcius.

Thanks

 

I grow gerberas outside. I think you would be better off doing the same.
TheMadHedger, how much light do they get?

 

I must admit that I had indeed thought of planting them outside.

They get a good amount of light - full sun for a few hours in the morning as they're in an east facing window.