Note that colour is NOT a positive means of identifyying coolant type. When buying you need to check the type and specification.
Is this just for a top-up or are you changing the coolant? Unless you know the service history of the car you cannot be sure what type is in the car.
If just topping up you can get "universal" coolant that will mix with any type. One brand is Prestolite, it's yellow.
If changing the coolant I'd recommend using the OAT "longlife" type but whatever you use a flush (fill and drain) with clean water is required.
Robert G8RPI.