look for lighting stores on google...
If you are in UK i found a site for a buddy of mine over there called Ebulb or ebulbs(google it) they sold him his daylight 6500k bulbs...quite cheap too
just look online for cfl compact fluorescent energy saving bulb 2700k (for flowering) and 6500k(for veg)
you sgould be able to get BC and ES fitment bulbs..also make sure you order the correct choice of 240v or 110v