We had a special link through our company website where you could order. Unfortunately, the time I was ordering was exactly when they were switching over to MYW (I think we got the info on Dec 31 and MYW started Jan 2) so it was very confusing. You could call Disney directly (again with a number they provided us), but you needed your convention number from your company. I have, however, seen threads here of how people have somehow ordered convention tickets without being with a convention, but don't know how they did this.
I know our tickets were $162 for a 3 day hopper, plus one visit to Disney Quest or Pleasure Island (NOT a water park). We used it at DQ on the 4th day before we flew out. My husband's 2 day after 2pm tickets were $78 - I think the one day was like $45 but I'm not certain. I know the 4 day convention hopper was quite a bit more (I want to say $218 or so), but included 4 visits to DQ or Pleasure Island instead of 1. If it had included all plusses, like the water parks, we might have gone for that, but we're not PI people, and I couldn't see DQ 4 times!