[TYPO3] Getting site running after Hacked

[Ian Fish]

Hello all,

One of my sites has been hacked.

I am not an experienced typo3 or linux user, although I have learnt 
enough (with the communities help) to set up typo3 and a few sites on a 
linux virtual server.
I am running version 3.8.0 installed via Fantastico
When the site was hacked I couldn't get in to the typo3 backend, but 
could still ftp to the site.
I found the following amended files:

www/typo3/index_re.php
www/typo3/index.php
www/typo3/index.htm
www/typo3/index.html
www/typo3/t3lib/index.html
www/typo3_src/t3lib/index.html
www/typo3_src/tslib/index_ts.php
www/typo3_src/tslib/index.html

I have replaced these files with backups.

There may be others, for example in the folder www/typo3_src there are 2 
folders called showpic.php and index.php that were amended about the 
same time the hack happened, I can't view or download these folders.

The site is now accessible, and I can log on to the backend, however I 
can only access the page and list views in the backend, the other pages 
load the hacked site in the main view window.

How can I get the site running again?
What do I need to do to stop the site from being hacked again?
Any other advice?

Regards,
Ian Fish