SEO for a new website

We are an upcoming eCommerce store designed on Magento platform. We are looking for services that will enhance our website’s search results. The goal of this project is to achieve 1st page results based on select keywords Some of the keywords we are in the market are of: Cpap machine, cpap supplies, cpap mask, cheap cpap machine, best cpap machine, affordable cpap, cpap help, sleep apnea assessment We want to start with an analysis of our website. We want to be advised on what headings, meta keywords, tags and SEO tools we should use to be more accessible to search engine crawlers. Secondly, we want a powerful link exchange campaign where you submit our website links to websites that have a PR of atleast 4+. We also want articles that are rich with our keywords to be published. We would like to know following: 1) What can you do to help us achieve first page search results? 2) How long will it take (in weeks) to be on the first page (Range of minimum to maximum) 3) Tenure of Agreement 4) How much would be the cost of services for the whole term of agreement. 5) What if you could not helped us to achieve on first page during the initial period as mentioned in point # 2. 6) What if you could not maintain our website on the first page during rest of the agreement period? Any questions and inquiries are welcome so that you are absolutely clear of what our goal is. Please let me know if you are willing to work on the project under the terms and conditions mentioned in the attached file.