There is (deliberately) no feature for 301 re-directs in Blogger.
I assume that you plan to delete the contents from Blogger when you have moved them to the other site (to avoid duplicate content problems.)
You could set up a custom 404 error page which tells human visitors which website to find the contents (under Settings > Search Preferences > Custom Page not found (edit link) ). Google will also follow this link to re-index the content at the new location.
And if you have set up the blog in Webmaster Tools, I believe there is a feature there where you can tell Google about your site moving. (Sorry, don't know the details of it.) But I don't think you can do that for each individual post.