Plopping more code into code that's already broken will result in one thing: BROKEN CODE.
It's the same thing with a pile of poop. Add more poop and you simply have a bigger pile of poop.
You will expand yourselves into a McDonald's outfit if you don't FIX WHAT IS BROKEN BEFORE EXPANDING UPON IT.
Fix what you ask? Take a look at the forums FunCom. See what your customers are saying about your game. See what they are saying about how you intend to 'expand' the game. Then you will see what the hell needs to be fixed.