Pages are now read only any other security advice would be appreciated.
Securing your site is something that requires more than using a few tips here and there. I'll give a few however.
I am not a security expert, but If the site's scripts are self written then you can start by read this
Security Guide.
If this is a third party script, then you'll want to keep up on updates. You'll also want to search regularly to see if there are any known vulnerabilities for the script at a site such as
http://www.securityfocus.com.
Having already been compromised, you may want to do the following things
1) Take the site down
2) Find out how the site was originally compromised. If you don't know then it's likely that it will happen again.
3) Depending on the level of access gained, you may want to change passwords for the databases,ftp,control panel etc. The associated email addresses should also possibly have their paswords changed if they are the same as any of the others.
You should be able to find sites that deal with (or have sections dealing with) overall security specifically, to get more opinions.
This doesn't have much to do with a PHP script you're writing so I've moved it to the Miscellaneous forum.