I'm the only executive, I have 100% of the shares, I have 4 employees.I built the prototype on my own and I'm almost launching.
This person has intense experience in tech but not as an investor. Should I tell the investor how much capital I need and how much Equity I'm willing to give? Or should I wait for the offer?
As your question looks right now, I think this is a high risk situation. You don't seem to have tried this before, and neither does your investor.
The most important part is having a shared, common goal for the business. In the case of a typical VC-to-tech-entrepreneur deal, that shared goal is explosive growth followed by a sale of the company. You goal doesn't have to be the same, but you have to be clear about what it is, and that your investor shares it.
For the specifics of how to have an investment, the best book that I know of is:
As your product is on idea stage, the risk is very high and so the shares of the investor will be. While starting up, the best option is to self fund your business if you can, because in seed investment, most people end up giving a large percentage of share in return of a small amount of money, and that causes problem when the startup need series B funding. Typically, you probably wont be owner of your own company and That is a hard fact.
You can refer to this http://www.forbes.com/sites/alanhall/2012/09/09/you-want-how-much-ownership-in-my-business/ Is says if your business is on idea stage, investors can rightfully ask for 50-80% of ownership.
If you can bootstrap your business, that will be the best option, or if you really need investment, you can first wait for the offer and then propose yours.