Our Gnostic Church is the Transcended Church. This church is found in the Superior Worlds. -Samael Aun Weor, The Perfect Matrimony
However, you can do some searches on the internet to find a Gnostic Institution, if they are holding public lectures. I would only suggest a school that maintains the three chamber system as established by Samael Aun Weor, and before committing to any group, really investigate what they are teaching and the quality of their teaching. "By their fruits you will know them."