Hi, Karen. These questions have been answered many times before, so you'll get a lot of information by using the Search function to look up old threads. To give you short answers:
No, you do not need to register the copyright yourself; in fact, you shouldn't. Your copyright exists from the moment of creation. When your book sells, and is in its final form, the publisher will register the copyright in your name. Registering the copyright for an unpublished manuscript is one of the Dreaded Signs of the Amateur.
No, you do not need to get your manuscript professionally edited. That, too, is one of the Dreaded Signs of the Amateur. If you expect to be published, you must be capable of editing your manuscript to publishable quality yourself.
It is not necessary to have an agent, but it's helpful. Many respectable, effective publishing houses still accept unagented manuscripts. An agent can, however, get your work read sooner, get you better terms in your contract, help you plan your writing career, and get your work seen at houses that don't accept unagented material.
If you look through the Index thread on the
Bewares and Background Check forum here on AW, you'll find links to many threads on finding a good publisher and a good agent, and many threads on hiring editors (why not to), and so on. Good luck!
ETA: Thanks to everyone who pointed out that I blundered and typed "professionally published" where I meant "professionally edited" above. Corrected now.
