Search engine results

I have wrote a basic search engine PHP script. I have created a mySQL database of the files which are allowed to be searched (Example: directory/file_name.html) When someone enters search criteria the mySQL database is opened and the various web site files are loaded one at a time, dumped into a variable and then using the eregi command check to see if there is a match. If there is it displays the web page title. I wanted to add some text from the file now. I wanted to add like 150 characters before the search string and about 250 characters after the search string. Is anyone able to help me with this? I wanted to strip out HTML so only plain text is shown. I essentially want to add a block of text like this paragraph under the web page title results which are currently displayed. Ron