According to the water height provided by the poster, the water height is 2 to 3 meters, the flow rate is only 7 to 8 liters, the power is too low, and there is no no finished turbines to choose from.
You can purchase a mixed flow or axial flow water pump with a flow rate and output pressure slightly lower than the data you provided to use as an impeller.
The generator only has a few dozen watts, so it is best to use a DC motor.
http://www.patent-cn.com/2013/11/21/94792.shtml?
You can use this portable hydroelectric generator HYDROBEE Search their site Web on GOOGLE and the product is already available, but it has been announced that it will not go on sale until 2014