If you don't know how to fully backup your blog yet. Then you should see this post first.
I will use my own online storage for this post which is Media Fire. You could choose from more other site too. Here are some (Rapid Share, 4 Shared, Mega Upload)

Step 1



Go to www.mediafire.com

Step 2



Click on "Upload to Media Fire" button.

Step 3



Click on "I'll Create an Account Now". Then register for an account, if you already have an account in mediafire, then just click on login.

Step 4



Just click on "Upload Files to Media Fire" again after the page has been reloaded.

Step 5



Choose the backup compressed folder.

Step 6



Click on "Start Upload"

Step 7



If you see this, then you have successfully made an online backup of your blog.

Also check out:

Using Your Backup to Restore Your Blog