If you have Halogen, you'll need a kit that includes the bulb and ballast. You'll also need an adapter for the H7 to accept the hid bulb. Unknown if the halogen projector you have is the same as the stock hid projector, which may or may not affect light output.
I have no idea on that kit, seems to get good reviews. Make sure you get the color temp you want, that link was pink. lol.
Jaydub -Here is a photo of the light output from my Cadenza. Brighter than the halogen set-up as well as the Factory. The bulbs are 5000k, the stock bulb color is a 4300k. I have at-least 90 feet of clear light projected forward. Retrofitting is a great option if your car doesn't come with factory HID projectors.