Add more soil to the pot, and get the light closer to them. They are stretching because the light is either too weak or too far away. I would also transplant them into separate pots, so they don't compete for root space. Hope this helps. ;-)
I agree with Ms. Fox they look like they have done some pretty good streching i would suggest moving the light maybe an inch to 2 away from them and yes more soil would help so you can cover them up almost all the way to the top but not quite