removing date and ID number from article title

I am a joomla newbie so apologies if this is something obvious.
I am trying to remove the -2011100528 from the url so it just uses the alias I defined. ( www.screenlaunch.com/contactus-2011100528/
Is there something I am missing as I thought it would just use the alias name unless it had non latin characters?

Solved by removing unique ID... but it has made me wonder is it better for SEO to have this as YES?

It's only needed if you need to add your site to Google news which require a unique URL identifier.