I'd suggest, that you change every single password relating to yours or any other admins account, your mySQL password, and your ftp/control panal password. It also might be wise to switch to another Forum software, such as Invisionboard (or vBulliton though I doubt you could afford that) These two are both made by commercial companies and will probabbly have better security. I can convert the phpBB2 database to Iinvision if u do decide to do this.