Also, in English this phrase would be: I had a dream ABOUT her.
In English it is: To dream about.....(someone, something, etc.)
But in Spanish it is: Soñar con.....(alguien, algo, etc.)
Saludos!
(We could probably go on at length about the simple past "dreamed vs dreamt" and as past participles as well, but this is a question posted about Spanish) :-)