That square light with the cage over it is probably a halogen, not a good light to use. If you're strapped for cash Wallyworld has some outdoor flood light bases, for about 3 bucks, they work great for the CFL's they have in the lighting section. I have seen up to 150 watt CFL's on the shelf about 8.80 each. You will have to trim some of the plastic off of the flood bases so the CFL's will screw in. Now the CFL's you want to get are the bright white ones, combined with a cool white, which looks a little yellow when lit up. You can screw a Y adapter in the flood base so you can use 2 lights in each flood base. This should work real well for ya. G'Luck wit dat shiz.
Nim