if you dont want to add more CFL's then at the very least pick up some type of floura light to go with the 3 you have. I picked up a 4ft floura light for $10 at fred meyer's and the bulbs were about $8 for 2 (i used kitchen and bath).
only used the light for about a week before i was eager to switch to MH lighting, but the floura did pretty well in conjunction with a UV light i had around!!
or do what the others said and get a splitter. Theres lots of sales on CFL lights if you look around. I saw some cfl's the other day 3 for $11. cant remember what the watts were,