few things.
you could replace both the sending unit and the gauge.
or if the sending unit is still good, you can purchase a gauge using that same range of ohms usually.

depending on if the sweep is up or down, you could buy a new gauge and gut it.
people have done it with volt meters and used the amp meter front on it.

you will have to see what the gauge backs and such look like and how you would fit the old face to it.

as for needing the circuit board, the car uses that because the vr is part of that board, but aftermarket gauges are generally 12 volts and don't require that.