There is indeed a moon goddess within the Wiccan religion. In British Traditional Wicca this is a specific Goddess whose name is never revealed to those who have not been initiated into one of those Traditions.
There are goddesses associated with the moon in almost every culture. In Greece it was the Goddess Selene and the Goddess Artemis. In Roman beliefs it was Luna and Diana. But you can find many more names at http://ancienthistory.about.com/od/polytheisticreligions/tp/MoonGods.htm
In other cultures the Moon was associated with a god rather than a goddess. As an example, in Japan the God of the Moon is Tsuki-Yomi
The symbol )0( represents the waxing, full, and waning moon. In Wicca it also represents the concept of the Triple Goddess as Maiden, Mother, Crone. The idea of the Triple Goddess is a modern one, not linked to any historical mythology, that is derived from the book of poetry called "The White Goddess" by Robert Graves.
As to whether you can worship both one of the Goddesses and Jesus I think that is up to you. However, in my opinion, it would be difficult to do since it violates many of the teachings of the Bible. I would ask why you feel a calling to worship a Goddess at all? If you do feel such a calling you might want to look into Sophia who is the feminine principle of the Divine in Gnostic Christianity.