Electric or pump?

[Jodes]

Hi,

Here's the problem: at the moment, I've just got a shower linked to the taps, but because the cold-water tank is directly on top of the hot one (both on the same level as the bathroom), the pressure is really low and if you lift the shower head up the hot water completely stops. I'm only little, but even I couldn't even have a shower at that height! So, I need to get a proper shower installed. However, because I'm conscious of the environment I don't want one that wastes a lot of water or energy, I don't know which is best to get. How much energy does a pump use and will that just waste water? Would an electric shower solve the problem, and does that use a lot of energy?

Thanks loads for your help!