Joomla is relatively easy to change the look of using Templates.

There are some excellent templates available at: RocketTheme Template Club

There are several places to get free templates to try it out.
Pick a few that seem to fit the look you want. Download. Then install it on your site through the Admin area. [Installers - Templates] It should be as easy as uploading the zipped file through the admin.

After you've tried a few free templates, you might want to pay for a few more professional ones. They generally have some extra features that are worth the few extra bucks. RocketTheme Template Club

Web Designers - You can save your customers money by using a pre-made template, yet still make a little on the template sale. Yes, it still needs to be customized for the customer's individual needs, but using these great templates gives you a huge headstart.

Webmaster's / Web Designers, Earn Money for Referrals Here!