Electric Piano software

[denshipiano]

In a music store i visitted yesterday i saw a Electric Piano with an intergrated screen showing not only the piano sheet but also a little miniature piano showing wich key you had to press and was pressing at that moment.
A picture of the piano: https://www.production-room.com/gfx/products/large/hpi7f.gif

So i have a Electric Piano myself (and a midi-USB converter cable to attach it to my tablet pc) and was wondering if anyone knows a program wich allows me to use my tablet computer in the same way the little screen on the electric piano in the image is used. Most important are the notes and that a lightweight program would be prefered as my tablet isnt powerfull.. at all..
I dont have a printer myself and printing sheets at the local convenient store costs roughly 1 dollar a paper so this is kind of getting inconvenient.

Thanks in advance for any tips or advice and excuses for my bad english. ^_^