I just did a quick search on the 'net and found this:

www.zetex.com/3.0/appnotes/apps/an1.pdf

which describes a 8w inverter for fluorescent lamps using a transistor. Obviously the output windings need to be changed! as well as some rectification etc to give DC. You don't need to use a Zetex transistor - something like a BD139 might be suitable for your app - if you have enough basic electronics knowlege, this might point you in a suitable direction. Or convince you to pay the money for an 'off the shelf' solution.