Figured there would be an easy answer on Google, but no luck. Most of the tutorials, while similar to what I need, don't work on Debian:
-bash: add-apt-repository: command not found
And the steps here: http://vjetnamnet.com/how-to-install-php-5-4-on-debian-using-dotdeb-repository/ get to
apt-get update N: Ignoring file 'dotdeb.gpg' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension N: Ignoring file 'dotdeb.gpg.1' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension E: Type 'Deb' is not known on line 1 in sources list /etc/apt/sources.list.d/sources.list E: The list of sources could not be read.