I'm afraid that if you really want to learn to play the piano, you will have to get a digital with weighted keys. Learning the feel of the action, and how to control it to produce the sound you want is an essential part of the game!
So... it's going to be digital piano. I can't recommend one, as honestly I've only played one -- a very nice Kawai -- and so I certainly can't comment on the merits of the various instrumets.