Often it takes time, effort, and many submissions to get published. It is not necessary to register your work with the Copyright Office to protect it. For a first-time author, the time to look for an agent is usually after a publisher has expressed interest in your work. Then, you'll want an agent to help negotiate the contract. Ask your publisher for a recommendation, or check the Literary Market Place or the Writer's Digest Guide to Literary Agents.
Many agents also have listings on the Internet.
With today's desktop publishing technology, it has become easy and relatively inexpensive to produce your own book. Unless you're experienced in graphic design, it's wise to hire a desktop publisher to produce a professional-looking product. Be aware that self-publishing means more than getting your book printed. Vanity presses take your money and various rights, and give you little in return. If you're willing to pay money to have your book published, do it yourself so that you can retain full control over the process, the rights, and the proceeds.