VERY QUICK php/Wordpress fix needed!

Hey guys, I have a VERY, VERY simple problem that I can't for the life of me figure out! What I want is on my home page on my WP blog, to show posts as excerpts in two identical, parallel vertical columns, but only posts from CATEGORY 3. Everything works, but I can't figure out how to work in the code to show excerpts from only category 3. Here are the two pieces of code, I just want to integrate these so it all works together.

I'll paypal whoever can complete this (only if it works!) $5 right now. Either post back here or PM me with the code and your paypal email and I'll send the money right away. Gonna be here for the next few hours. Thanks!

<?php
   if (is_home()) {
      query_posts("cat=3");
   }
?>

Code (markup):

<?php if (have_posts()) : while(have_posts()) : $i++; if(($i % 2) == 0) : $wp_query->next_post(); else : the_post(); ?>

<div id="left-column">
<?php the_excerpt(); ?>
</div>

<?php endif; endwhile; else: ?>
<div>Alternate content</div>
<?php endif; ?>

<?php $i = 0; rewind_posts(); ?>
<?php if (have_posts()) : while(have_posts()) : $i++; if(($i % 2) !== 0) : $wp_query->next_post(); else : the_post(); ?>

<div id="right-column">
<?php the_excerpt(); ?>
</div>

<?php endif; endwhile; else: ?>
<div>Alternate content</div>
<?php endif; ?>

Code (markup):

 

I think I can figure it out, if you could send a more complete description to I will help you out.

 

Try this:

<?php if (have_posts()) :query_posts($query_string .'&cat=3'); while(have_posts()) : $i++; if(($i % 2) == 0) : $wp_query->next_post(); else : the_post(); ?>

Code (markup):

PM me if you still need help.