Controllers aren't "faster" or "slower", though if they don't provide enough power to the motor to overcome air resistance at the speed you want to go under the riding conditions you have (none of which we know), you might need a bigger one.
However, it *is* possible that for legal reasons your controller is designed to limit speed. You can easily test this by measuring speed with the motor wheel off ground at max throttle, vs max speed on level ground while riding. If it's speed limited, this speed will be the same either way. If it's not speed limited, it'll be significantly higher off-ground. If it is speed limited you can replace just the controller with one that can do all the same things yours does now, same ratings, etc., (or higher for amps and watts), and that has no speed limit.
Motors have a kV, or RPM per Volt, which means that for a certain system voltage, there is a maximum speed it can possibly spin at. A different motor at the same voltage may spin faster or slower. The same motor at a different voltage would spin faster for higher voltage, or slower for lower.
Similarly, a larger diameter wheel spins faster, all other conditions the same, but with lower torque. A smaller wheel spins slower, but with higher torque. It's directly proportional, so if you need speed to go from 45 to 65, you'd need a wheel 65 / 45 = 1.4x bigger.
So there are a few options, depending on the power needed to go the speed you are after, under your specific riding conditions. Note that if the power (or anything else) needed is higher than any part of your system can produce or handle, you would also have to replace those parts.
--Replacing the motor with one capable of the higher speed at your present battery voltage. This is the "simplest" option, assuming you don't need any more power to go that speed than your vehicle is presently capable of.
--Replacing the wheel on the existing motor with a larger diameter one, assumign there is space to fit this, and the geometry change to the steering/etc doesn't make the vehicle unrideable/etc.
--Replacing the battery with one proportionally higher in voltage (at least 1.4x) than what you have. (this would almost certainly require replacing the controller, as it is unlikely to be able to handle that voltage. Similarly, the DC-DC that runs your lights, if the vehicle has one, also would need replacing. If the lights are run directly from battery voltage, you'd have to replace them with ones that can handle it as well, or with standard 12V ones and a DC-DC to run those off the high voltage battery, etc).
Note that it is very common for the parts of a vehicle to only be designed to provide what is necessary to make it do what it was sold as. So it is quite possible that the significantly higher power demand of the faster speed will require replacing battery, controller, and motor (though the motor may well be able to handle much more power than it's "rating", it would get hotter, and you might want to monitor that to be sure it won't cause a problem if it's not replaced). The battery may either sag in voltage so much at the higher power demand that it wont' reach the speed you need even with new motor and controller, or it might just shut off from overcurrent, or it might not have any protections for that and just be damaged by the higher load on it.
Note however that making this vehicle go faster, by any method, may make it illegal where you are, so you might want to check on the consequences of that first.