And how many times do you have to be told that it's not either/or, it's and/both.
The Bible over every book, yes. The teachings that we hold are supported in Scripture, either implicitly, just like your acceptance of the Trinity, or explicitly, like the True Presence of Christ in the Eucharist.
Proper interpretation, and interpretation is a result of the sum total of Scriptures, reason and what we know about God through the Scriptures. I would also add that nature, the order of things in this world and love itself, as we experience it here, shed light on the One, True God and His plan for us.