Hello,
When I first came on to this forum, I basically asked the same question. I now realise how difficult it is for other people to suggest pieces for you. Music is very personel. I would buy a collection of CD's and pick something you like, that you feel is a little beyond your capabilities. Then you are learning something new and stretching yourself.
You play Fur elise. If you like Beethoven, (The Greatest), may I suggest "Moonlight Sonata" Mvt I.
Sorry for not being much help.
Cheers,
Shorty.