Combining queries to increase efficiency

[emperorevil]

Here's the situation: It's a simple news script, which is based off of a forum, all in one table. The first column is forumid, which is always 1. The next is topicid, which is different for each news post. The postid is 1 for each topicid for the main message, and continues on for each reply to that message. The rest is standard information:

So I would get the sql table for that starting off by doing this:
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$query="SELECT topicid, username, subject, timestamp, message, FROM posts WHERE forumid=1 AND postid=1 ORDER BY topicid DESC LIMIT 12";
$result=mysql_query($query);
while($row=mysql_fetch_array($result)){
// output the information //
}
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Then I want to tell the viewer how many replies to each news post there are. So I would count the number of posts in the news forum for that topic by placing this inside the while() loop:
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$query="select count(*) from posts where forumid=1 and topicid='$row[1]'";
$result=mysql_query($query);
$numofreplies=mysql_fetch_array($result);
$numofreplies[0]--;
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Now here's the tricky part. How can I incorporate this extra query I have to run into the original query? I want the number of replies per topic to be another column. That way this page only has 1 query it has to execute instead of a bunch.

I hope I explained it well..