By default, the latest version of WordPress is pretty darn secure. The development team of WordPress has considered anything that might have been added to any fix wordpress malware virus plugins. In the past , WordPress did have holes but now most of them are stuffed up.
Everything you have worked for will proceed with it should the server of your site return. You will make no sales, get signups or no traffic to your website, and in short, you're out of business useful reference until you get the website back up again.
You must create a new user, before you can delete the default admin account. To do this go to your WordPress Dashboard and click on User -> Create New User. Then enter all of the information you need to enter.
Note that this last step for new installations should only try. You have to change of the table names within the database if you would like to get it done for installations.
But realize that security is something you must start thinking about. Do not just be the type that is reactive, take action to start today protecting yourself. Don't let Joe the Hacker make your life miserable and turn everything in creating come crashing down in a matter of moments that you've worked so hard.