Yep...You can buy a "retrofit kit" or get all the parts from a lighting store, etc. Depending on the corals you are doing, you are going to either need Power Compact Lighting or Metal Halide's. Power Compact is pretty expensive and Metal Halide's are very expensive, but are the most accurate to the sunlight, that you can give your tank. If you just want"basic" soft corals you could probably get away with roughly 170 Watts, but thats pushing it and your corals wont be at their true beauty they can be at. You have a medium/ sized tank ... So I m going to say that if you have a little over of 200 Watts of light, then you should be fine for the "basic" corals ... But if you are going to get many corals and many harc corals, i would look into a lot more wattage, or MH (metal Halides)
Hope that helps you a little or a lot ...
-Aaron