Hello, Mr TheSoloGuide is right in what he suggests, and a business plan, while it may seem daunting is really indispensable, even if don't intend to seek financial help from outside. As the Cat said to Alice; "if you don't know where you are going, how will you know when you get there?" Yet many start ups adopt this mentality and then wonder why they fail.
On the surface it seems a huge task, and, to be honest, it should be fairly well in-depth, but like most things, if you do it step by step it becomes manageable. As well as his great site, there are on line guides available and many years ago I used a free software which was basically a template, it was a little easier.
In so far as IP is concerned, it is a headache, but think yourself lucky you are not in China! You may be able to get a confidentiality agreement as suggested, but ultimately, business involves some sort of risk, the higher the rewards the greater the risk. You can lessen those risks by doing your homework, check out prospective lenders, talk to their past clients if you can, ask a lot of questions. If they don't like to answer or can't, keep shopping.
I am not in US so can't advise on the best investors, but unless you enjoy a REALLY good credit relationship with your bank, my experience is these are the least useful resource. Do a GOOGLE for "venture capital investors" there are hundreds of them, or were 2 years ago, sift through and go from there.
Lastly, although it is not one of your actual questions, you talked about help with national and international marketing. We offer what we call Angel Venture Marketing, works the same as a capital investor except we put or advertising skills where are mouth is. Obviously this is no use to you, BUT I don't believe there is any such thing these days as a unique idea so maybe there is a marketing firm in US that will work with you along similar lines?
Hope this helps and good luck.
