You'd have to check the Yoyo website to get the specifics. But at this time, if you have the modules(or the Master Collection) of GMStudio, you get windows, mac, linux(Ubuntu), HTML5, iOS, Android, Windows8(Javascript), and windows phone. So if you really insist on consoles like PS3/WiiU, you won't be able to directly use GameMaker for that. But in reality, you need much more than just game code to make something for most consoles, including SDKs, developer licenses, etc... and this applies to any coding manner, including Unity3d or any other engine.

Considering that GM is appealing to you, I'd stick with it. Assuming you got really good and were able to get the other requirements to port to consoles, then I'd think you'd know enough programming by then to use something other than GameMaker. Take smaller steps, and learn things as you go.

As far as GM's capablities, I'd say you can do much more than just prototyping(though it has been used for that purpose). Many recent apps have been creating using this software, by YoyoGames and other people as well. It is also a quick way to make HTML5 games. In this, it is similar to Unity3d because one code base generally can be used for all the available platforms, with the main exception being input porting and some performance considerations. It has been said that GM is the 2d Unity though.

1st question: If i want to consider a console port do i need to use a different Game programming tool?

Very probably, unless YoYo Games release additional export modules supporting the platforms in question.

As per the above reply however, you should be aware that there are other issues to be considered before deciding that a console port is definitely something you want to do.

2nd Question: Is Game Maker only good for making prototypes?

Not at all, although that's certainly an excellent use for Game Maker and similar packages. There are a growing number of good quality games being sold that have been made with this sort of software, and it's my understanding that Legend of Fae and Serious Sam: The Random Encounter (which you'll notice are both for sale via Steam) were both made with Game Maker. I'm sure there are numerous other examples.

If programming isn't your thing and you're comfortable with Game Maker then there's no reason you shouldn't continue to pursue it.