If the cpanel thing doesn't work anymore, you still can download your whole Pixelpost installation via FTP from Server to your Computer. Make sure that you download ALL files and folders of the Pixelpost package!
You have to backup your database too, see here how it is done:
http://www.pixelpost.org/docs/GettingStarted/Upgrade
Create a database in E2 account (or get the access data of an existing one). Replace the access data of your backuped includes/pixelpost.php file with the new access data. Don't change the table prefix!
Now you can upload the whole file backup to E2 using FTP. Don't forget to upload the changed pixelpost.php!
Last step: go into the mysqladmin or phpmyadmin of your E2 database and import the sql file from the old host. If you run into troubles doing that, I am sure the people at E2 can help you with that.
After doing so, you should be able to reach your photoblog again and keep on blogging