Drivers can be found in quite a few places. It depends on how much you are willing to spend. For low budget, the Chinese made drivers work well. Deal Extreme (DX) is a popular place. If you want to spend a little more money and get a driver that will be more reliable and with a nicer firmware, USA made TaskLED drivers are nice. These are just a few places where you could get a driver.
It doesn't look like there is any heatsinking in that flashlight either. To do it properly you have to have a way of keeping LED cool (usually a large chunk of aluminum).
I'll give you my opinion based on the few pictures you posted. The light looks extremely cheap. In my experience it is not worth modifying cheap flashlights. By the time you spend money for a new LED, driver, and heatsinking and all the time trying to cobble it all together, you are better off buying a better light.
Having said that, I enjoy projects like this and think it is good for people to do them. It doesn't seem like you have any experience with this and a project like this a good starting place. It doesn't have to be done perfectly with heatsinking and you don't need to get top of line LED and driver. If you trim costs, a project like this is one of the cheaper ways to get into flashlight modding. If you are looking for the best value for your money for an upgrade then IMO modding the light is a terrible idea and you should just get a new light. If you are looking for a little project to do that will give you a slightly better flashlight then modifying the light is a good idea.
I spent in the neighbourhood of $300 for the parts to make a custom modified MagLite. I hardly ever use it so most people would consider it a waste of money but I thoroughly enjoyed the planning and construction of it so to me it was worth it.
