How do I fetch info from datastore in a plugin?

[Kriminal]

I want to show stats from my board, like it's explained in this mod:
But, I want to save 3 of the 5 queries, refreshing stats every 5 minutes.
So, the only two stats whose stays "live" are the "online now"; the other 3 (total threads, total posts and total members) will be updated every 5 minutes and saved in datastore.

I did the following steps:
1) Create a ministats.php inside cron folder:

PHP Code:

  $numbersmembers = $vbulletin->db->query_first("SELECT COUNT(*) AS users,MAX(userid) AS max FROM " . TABLE_PREFIX . "user");  
  $ministats['numbermembers']= number_format($numbersmembers['users']);  
  
  $counter = $vbulletin->db->query_first("SELECT COUNT(postid) AS posts, COUNT(threadid) AS threads FROM " . TABLE_PREFIX . "post"); 
  $ministats['totalposts']=number_format($counter['posts']);  

  $countthreads = $vbulletin->db->query_first("SELECT COUNT(*) AS threads FROM " . TABLE_PREFIX . "thread"); 
  $ministats['totalthreads']=number_format($countthreads['threads']);

  build_datastore('ministats', serialize($ministats)); 


2) Create a cron task to execute the php. I noticed that it works (the stats are saved in datastore table)

3) Create a plugin that:
a - execute a sql query to fetch the online members
b - retrieve info from datastore

The plugins is allocated in "global_start" hook, and this is the code:

PHP Code:

// online users  
$datecut = TIMENOW - $vbulletin->options['cookietimeout'];  
$headerguests=$db->query_first("SELECT COUNT(*) AS count FROM " . TABLE_PREFIX . "session WHERE userid=0 AND lastactivity>$datecut");  
$headerusers=$db->query_first("SELECT COUNT(DISTINCT(userid)) AS count FROM " . TABLE_PREFIX . "session WHERE " . TABLE_PREFIX . "session.userid>0 AND " . TABLE_PREFIX . "session.lastactivity>$datecut");  
$headerguests=$headerguests[count];  
$headerusers=$headerusers[count];  
$totalonline=$headerguests+$headerusers;  

// info from datastore
$ministats = unserialize($vbulletin->ministats);
$numbermembers = $ministats['numbermembers'];
$totalposts = $ministats['totalposts'];
$totalthreads = $ministats['totalthreads']; 


The online members info retrieves correctly, but the info from datastore not.
So, my question is: how I do to fetch that info in the plugin?

Thanks in advance,

PS: In the topic title, I put a "g" instead a "f". I'm sorry.