Water Leaks - Windows and ceiling of first floor of stucco home.?

I have put sealant around the top of the first floor windows outside but still get a leak in the same spot inside - not sure why? Also, just noticed after a heavy rains that my ceiling was leaking(first floor) and there was nothing causing it from second floor. Could this be due to the stucco being poorly installed and it is leaking in and following along a beam? Any suggestions on how to handle would be greatly appreciated, as I am not that handy around the house and do not want to get screwed by someone if I call them to look at it. Thanks