How long it takes to re cache is really pretty directly related to how long it is until it re-crawls the site/pages. Like Ryan said, have you linked/confirmed the site with Webmaster Tools? You should be able to see crawl stats there. In fact, if you have added the site, submitting an XML sitemap via your webmaster tools account like Ryan mentioned would be good, but also... As you have redesigned the site recently, how are your writing skills? If you can string a few paragraphs together coherently, then consider writing a press release about the site's redesign. You can find info on how to write a press release via a Google search, but basically keep it pretty professional sounding, have an intro paragraph that explains in a few words (2/3 sentances) what t whole piece is about, and finish off with an 'About [company name] section, including a link back to your site. If you can spend an hour doing that, then submit it to 1 or 2 free press release sites (make sure t are Google news approved) and Google will find/crawl the link to your nice, newly designed site pretty quick, which should help to expediate the re-caching somewhat.
If t were to create a site in Google's new web standards language, would you do so? I don't think Webmaster Tools will be necessary, as a lot of these sites are just built using content management systems, but if you have any doubts... you certainly don't want to use tools that have a built-in crawler that crawls and analyzes the whole site. If I create a new website/site in Google Webmaster Tools, what will be the chances of the site being crawled in about three months? If you don't re-crawl the site regularly to make sure all the pages have been crawled, you'll be fine for a few months. After that, Google starts getting really conservative when it comes to re-crawling sites, and it will take about three months to three years for a new website to be crawled. It happens over hundreds of thousands of pages, so.