When you have a dream in which you see Durga then you can rest assured that it is going to have great significance even if you are not a practitioner of the Hindu religion and this is solely because of the power that she holds as a symbol rather than just anything else. Regardless of whether you are Hindu or not though, this does not downplay the significance of Durga in dream interpretation.
If you have a dream about Durga then this means that you feel supremely feminine and find power in that. This is a dream that usually women have, and you generally have to be familiar with the Durga before you can dream about it so clearly. But basically the durga is a representation of strong radiant feminine energy and power over all other things. If you feel like a strong woman right now then this is why you are dreaming of a durga.
Durga is a goddess that you may be inclined to forget about since most people only know of Shiva unless they are a Hindu and even then it can be hard to keep track of everyone in the spectrum of all of the Hindu gods and goddesses. Fortunately one of the most important things to remember about Durga is that she should not be forgotten. She is an extremely powerful force and her marriage to Shiva should not discount her own significance in any way. It can be hard to be under a powerful man like that but it does not mean she loses significance. Perhaps you are having this dream because you feel overshadowed by a man.