If I got my novel published, what's the likelyhood it will sell?

[Lori]

Congratulations! What a wonderful achievement

Well, if you self-published your work, you're going to need to do your own marketing and advertising campaign, which can be very difficult. You need to get the word out there, and Twitter is a good start, but you should organise who will sell your book in their store, book signings etc. etc.
If, however, you were lucky enough to have a publisher buy your book, then this should all be arranged for you. Although I think you should still advertise on your Twitter, Facebook or Myspace.

Congratulations; keep writing, and good luck with the sales!