[Apache downloading PHP files instead of rendering them after update from php 5.3.3 to 5.4]

I have some scripts that need to use a newer version of PHP, Im running Debian 6 which has PHP 5.3.3 support, I found I could install php 5.4 using https://www.dotdeb.org/instructions/ packages. This worked, it updated my PHP to a newer version, the only issue is that when the install completed apache now downloads the PHP file instead of rendering it, Ive been troweling google and stackoverflow and servefault for hours now and I cant find a solution.

Im guessing this has something to do with the Apache configs, but I don't know what to do.

tom@vps:~$ dpkg --list |grep -E '(apache)|(php5-)'
ii  apache2                                  2.2.16-6+squeeze12           Apache                                                                                                                     HTTP Server metapackage
ii  apache2-doc                              2.2.16-6+squeeze12           Apache                                                                                                                     HTTP Server documentation
ii  apache2-mpm-prefork                      2.2.16-6+squeeze12           Apache                                                                                                                     HTTP Server - traditional non-threaded model
ii  apache2-utils                            2.2.16-6+squeeze12           utilit                                                                                                                    y programs for webservers
ii  apache2.2-bin                            2.2.16-6+squeeze12           Apache                                                                                                                     HTTP Server common binary files
ii  apache2.2-common                         2.2.16-6+squeeze12           Apache                                                                                                                     HTTP Server common files
ii  libapache2-mod-php5                      5.4.43-1~dotdeb+6.1          server                                                                                                                    -side, HTML-embedded scripting language (Apache 2 module)
ii  php5-apc                                 5.4.43-1~dotdeb+6.1          apc mo                                                                                                                    dule for php5
ii  php5-cli                                 5.4.43-1~dotdeb+6.1          comman                                                                                                                    d-line interpreter for the php5 scripting language
ii  php5-common                              5.4.43-1~dotdeb+6.1          Common                                                                                                                     files for packages built from the php5 source
ii  php5-gd                                  5.4.43-1~dotdeb+6.1          GD mod                                                                                                                    ule for php5
ii  php5-mcrypt                              5.4.43-1~dotdeb+6.1          MCrypt                                                                                                                     module for php5
ii  php5-mysql                               5.4.43-1~dotdeb+6.1          MySQL                                                                                                                     module for php5
rc  php5-suhosin                             0.9.32.1-1                   advanc                                                                                                                    ed protection module for php5