Solo Scriptura (Scripture Only)...truth or hogwash?

What is the foundation of all truth? I am sure that my protestant brethren will say, "The Bible" However, the Bible itself indicates that the foundation of all truth is the "Church" (I Timothy 3:15). Since Jesus died and ascended into heaven around 30 a.d., and the first book the New Testament (probably I Thessalonians), was not penned until probably 55 a.d., what was the authority to look during these 25 year...the New Testament did not yet exist. The way I see it, the "teachings" of the apostles were just that, their "teachings" some where written (NT), and some were spoken (tradition). Either way, loxically, the Bible came from the Church, and not the Church from the Bible. (II Thessalonians 2:15: "So then, brothers, stand firm and hold to the teachings we ped on to you, whether by word of mouth OR by letter")