Top 3 Google for Roommates Site

I need to have my site [login to view URL], a PR 5 with about a 1000 links already, position # 12 on Google, 2-21 on Yahoo and 3-8 on MSN to rank in the top three "natural" spots for the term "roommates." This position should be obtained through ethical linking practices, etc... And needs to be maintained for a minimum of 3 months. Once 3 months has been paid and positions are maintained, a bonus of $20 may be applied for each month that rankings stay if the developer would like to continue. This site is out of the "sandbox" and ready to go. Should be an easy project for a good SEO person. I just don't have the time to complete this project alone. Any on-site changes will pass through me directly. No site-access information is to be provided. Again links from only "relavent," ethical sites, no link farms, etc...