SEO and google PPC

I am planning to hire a good SEO person. I wanted to know if there is anything else we can do to help us in rankings. Currently we pay google for sponsored site listings. Is there a formula for how much we can pay per click per day to really come up number 1-5 as sponsored links. This year we really want to try and grow our internet business and are looking to make all the efforts we can to come up in the top listings when people search for the items we sell. we are open to all suggestions and would look to hire you to help us with this goal. I hope to hear from you with any suggestions. We had a person submitting to Search engines 3 months back. That's all we have done so far in SEO point of view. Please list your action plans if you need the domain name I can give it in PMB.