If you really need to turn a full 360 degrees perhaps you could use a sail winch servo which does have positional control, usually over about 6 full turns. Or else add an encoder to your geared motor (aka continuous "servo" which isn't really a servo any more).
Or alternatively if you want to do 360, stop for a while, then another 360 and keep doing that perhaps a stepper motor would be better.
It really depends on what exactly your project, whatever it is, needs to achieve.
Steve