My husband and I built a new house 6 years ago; we received a certificate of occupancy from our township . Do we need a title for the house or the COO is enough proof of the ownership?

Hi,
Yes, in most states, you need a Deed, in both your names, for the property and the house.
I would check with your local courthouse, with the property tax office, or Court Clerk's Office, to find out how to get a Deed.
The Certificate of Occupancy, in NJ, only allows a person to move into the house. It's, more or less, just a township certificate specifying the electrical connections, etc, are OK, and more in the way of Building Standards are met.
Here is a link with explanation:
http://www.cherryhill-nj.com/government/departments/code-enforcement/code-enforcement.asp
I do wish you the best.