To open in your own site you could do this.
Instead of the full post url to the WP installation, you have a url that has the post ID only...
post.php would be a script that uses $_GET['wppostid'], if it is not set in the url it could display a notice and possibly a list of your latest posts.
If the ID is set such as in my example. Your page would then query and get the entire post content using the post ID passed by url.
Know much PHP?
This approach above is fine. It may suit you. The approach I linked to is basically the idea that your entire post is on the page, you just don't see it all. User clicks then it appears without changing page.
Also I don't think your allowed to discuss money on here ;)