Welcome to WoW! I hope you've enjoyed your last couple months of playing. Here are activities you can do over the next few months:
* Level an "alt". An "alt" is second (or third or fourth) character after your main. Many players like to do so in order to try out different classes or specs. For some people, an alt today becomes a main tomorrow!
* Run old raids. Did you know that there are old raids that you can run for fun items and gear? Some of them can even be soloed!
* Challenge Mode dungeons are a new feature this xpac, they're timed events to see how efficiently you can complete one of the heroic dungeons in MoP. The name is appropriate, they are a Challenge!
* Did you ever play Pokemon? Well Warcraft has its own version, called Pet Battles. They're easy to get into and you can collect a whole lot of pets to play with.
Those are just some ideas, I'm sure other people in this thread have provided different things you can do.