Wordpress update script

I need an update script that allows me to find CASE SENSITIVE text and update text outside HTML (without breaking the existing HTML) in a wordpress database inside table wp_posts. The purpose of this script it would be to replace word(s) in html by a text link IF NOT inside all these 5 example tags. Take for example these ones: Example 1: Example 2: My link word Example 3: This is my h2 title Example 4: This is my bold text It also need to exclude the description field inside this video short tag player to prevent links from being created inside my video descriptions. Take a look at the code: Example 5: [flv-player video="[login to view URL]" splashimage="[login to view URL] " width="530" height="360" description="My video description" player="3" autoplay="false" loop="false" autorewind="true" more_3="showtime=0&showplayer=autohide&showfullscreen=0"/] The script must contain four variables to be edited according the preferences: Field 1 example: $StartDateForBeginningQueryPosts = "2013-01-16" Field 2 example: $EndDateForStopQueryPosts = "2013-05-23" Field 3 example: $keyword2findfor ="keyword 2 link" Field 4 example: $html2replacethekeyword ="My keyword 2 link title" It also must output the number of text replacements once the queries are executed and be called to execute by browser. Example: [login to view URL] NOTE: This is a wp database and the script must update it without breaking the existing html as mentioned on the above 5 examples.