Using wp-query on a external page

I have a wordpress blog and a portfolio website. I want some posts to appear on my portfolio website. There for i have written a simple wp-query:

$my_query = new WP_Query(‘cat=4&showposts=3’);
while ($my_query->have_posts()) : $my_query->the_post();

The information of this Query has to appear in a “json.php file” that’s in the portfolio website.

How do i get the external page to recognise the “$my_query” ?

(the blog and the portfolio website are on the same server)

Thanks in advance