The fix malware problems free Codex has an outline of what permissions are okay. Directory and file permissions can be changed via an FTP client or within the administrative page from the hosting company.
There are numerous ways to pull off this, and a lot involve re-establishing databases and much more and FTPing files, exporting and copying. Some of them are very complicated, so it's important that you go for the one that is best. Then you may want to check into using a plugin for WordPress backups if you're not of the persuasion that is technical.
While it's an odd term, it represents a task. We're not simply being obsessive-compulsive here: servers go down every day, despite their promises of 99.9% uptime, and if you've had this happen to you, you understand the panic is it can cause.
In addition to adding a secret key to your wp-config.php document, also think about altering your user password into something that is strong and unique. WordPress will let you know the strength of your password, but include numbers, use upper and lowercase letters, and a great idea is to avoid common phrases. It's also a good idea to change your password regularly - say once.
You do not always consider needing security site web when your website is new but you do need to protect yourself and your investment. Having a site go down and not having the ability to restore it quickly can mean a loss of customers who can't find you and won't remember to search for your website later. Do not let that happen to you. Back up your site as soon as you get it started, and schedule frequent backups for as long as the site is operational. That way, you'll have WordPress security and peace of mind.