7 day up to several weeks that is - extensive work within your website - just like re-design efforts...
Your site does not even feature a handful of keywords, your page titles are mostly repeated, some pages are better cut into three or more thus gaining again momentum if done right with search engines and directories. If you want to get in touch with me - do so free of charge and without any obligation - else go and trust the SEO guys and ask for all the references - you want beat them beat you at the end, be assured. Without severely going into your pages - any SEO effort you ever pay is worthless I say. It should have been done when the site was created:( I wonder what statistics you are shown of your website's performance and what parameters are you going to use to charge work performed by the SEO guys. Ask me, I do answer your questions:) Else be ready to waste your time and money with SEO guys. Cheers - for a change, a non profit roll all over!