Precisely. However, the Old Testament is subordinated to the New. It is said to be "pointing" to, or "prefiguring" the "real thing." Jesus even says that Moses wrote about him but he doesn't tell us where. Some diligent scholars have "found" the verse which, just as Isaiah's verses, requires a lot of out-of-context imagination.
To the Church, the Old Testament is a pedigree, a claim to inheritance and a certificate of authenticity. Without it, Christianity would be just another new revealed religion with nothing to fall back on. Christianity was a messianic Jewish sect that used OT prophesies as "proof" that Jesus was the anointed warrior king who will fulfill the OT messianic prophesy of reestablishing God's Kingdom on earthanother name for Israel. [See Acts 16]
Though I appreciate the back-up, it saddens me that you have lost your faith. I know better than to try to preach to you, but I hope that G-d guides you to where He wants you and that you will re-learn the faith you once had--wherever you find yourself.
Hope that didn't sound insulting.