Here's the scoop (pun intended) on protein...
The [ususal] recommended amount of protein for strength athletes is roughly 1gr of protein for 1lb of lean muscle. So, a top level natural bodybuilder would require somewhere around 180 grams a day. So your level of 150gr is probably pretty close to what you need.
Protein is NOT a magical supplement. If you take more than the required amount, it doesn't turn into extra muscle growth, despite what the magazines tell you
Carbs are not the devil and won't magically make you gain fat just because you eat them. They are an easy way to increase calories, and when it comes to gaining (or reducing) size, calories are KING!