Well, it's like this... You have to have at least an idea of dealing with music and midi on a computer... do you have that kind of experience?? If you don't, then this will be a learning experience, like anything else in life that you've never done... If you've done music and midi on a computer before, and you've used soft synths and sequencers in which you edited wav files, then its a lot easier...

But when you're saying that your laptop is on top of your acoustic piano, and that you don't want to buy another keyboard, I think you're the learning experience type.. You haven't had experience with this type of stuff before and you're going to have to learn to use it to get the maximum benefits... But it's not that horrible and benefits will far outweigh the inconveniences of getting out of your comfort zone... And the benefits of being able to practice with actual harmonic instruments is a lot better than just having a drum machine metronome...