You should be able to buy along screwdriver from any decent tool shop. But you’ll need a little more information - the length and what tip it is.
Bought my stuff at builders.. must say the hex driver (general) and security bits (comes with extender) has helped me take apart most appliances to fix blown fuses, pulled cables etc.
But there are still 1-2 types of screw heads that I’ve not found an appropriate bit head for.. thankfully just Ellie’s stuff