I'd say stick to drumming for a bit longer. I played drums for only a year about 7 years ago before having a long instrument hiatus and got into playing the guitar & bass 3 years ago; and I still have more than a parking lot full of stuff to learn for either instruments. People need good drummers, as well as good bassists, so you can't go wrong with either. If you must, learn a little guitar, but the dirt these past many years is that guitarists are a dime a dozen. I'm pretty sure you can find a 6-string slinger to buddy up with to compose songs together with, or at least steal some knowledge from him for free.
