Gumpa, in the aquarium world, heat is also an issue from lights, and for some reason here, we have all been thinking about taking care of it from the inside... are we all nuts?
It just flashed into my head...
1st, get yourself some 5 inch cooling fans from the hardware store, if you cant findem there, you'll have to do some wiring, and get them from a computer supplier.
If your lights are under a hood, or encased in plastic, or what not, you'll need to cut vent holes, and place the fans over them. I won't go into electrical wiring here, so don't even ask, I am not a licensed or bonded electrician, so if I got someone electricuted, I would be open to one heck of a lawsuit... so find out how to do it from someone in the know...
Any how, get your fans wired up and turn them on. THe air moving over your flourescent bulbs will pull heat away, and evacuate it into the room. You can also set a fan up, even with some ducting if you want to get crazy, to PUSH air in.
regardless, this method pulls your nice cool air from your house into the lighting fixutre, dissipates heat, and pumps it out into the room, where it is again cooled by your air conditioner...