surgery will be necessary for you. Remember, however, that artificial valves are never as good as natural valves. So, the timing of the surgery is critical. Surgery should not be too late (high risk, no benefit), nor should it be too early (lower surgical risk, but problems of artificial valve). Also, post surgery, there is need for long term drug therapy and monitoring of blood tests.
Ideally, if you are really asymptomatic, the timing of surgery would depend on your echocardiographic parameters (LV size, LV function, etc).