Bookmark a POST request
Save the page with the form locally on your hard drive. 

You will then need to modify the source code to replace the textbox with a hidden field that has the same name and id as the text box and with a value of what you are searching for.   eg

&lt;input type="textbox" id="searchtext" name="searchtext" /&gt;


and replace it with

&lt;input type="hidden" id="searchtext" name="searchtext" value="343434" /&gt;


Replace "343434" with whatever you are normally putting into the text box.

Save this file.  And book mark it.   When you visit the page, you should just need to click the submit button and it will send the form along.

High chance that this won't work first time.  But let me know and I can guide you though any other changes that need to happen.  If its a publicly accesible site, let me know the url and I can help you out quicker.