Not sure what your stock bulb is in this scooter, but...
If it's an H4 Halogen, there are several good bulbs available the would produce more light. I would stick with major manufacturers though (i.e PIAA, Phillips, Sylvania, Osram). A word of caution, some of the high performance bulbs will pull more power and generate a lot of heat, which can cause problems with your wiring and/or housing being damaged by the heat. Likely shouldn't go more than 65W powered Halogen.
I went another route, I installed a full HID conversion with this kit...
http://www.amazon.com/gp/product/B00CQCEF60/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1
It is a 35W HID kit that produces a terrific amount of light and throws it pretty far down the road. The electrical hookup and ballast mounting was very easy, the light bulb base required a bit of work with my Dremel tool on the bulb retaining ring in order to complete the install.
A word of warning regarding HIDs. If installed in a standard reflector bowl housing, it can create light dazzle for oncoming traffic. On my Fly it doesn't seem to be an issue as I adjusted my headlight aiming downward a bit.