I probably could for 3-4k but I would need to know more about the site. (the domain age, is the keyword in the domain, how many links do you have now, what kind of content do you have on the site, are you willing to make changes to the site) It could take as long as a year or more to as little as two months depending your answers. I have beaten competition harder then this already though. I am not expecting to hear from you though because from your post it looks like you are looking for a magic pill not white hat seo.