Add Referring page to poll?

Hi.

Just added Advanced Poll to my site. It's great! Been searching through the forum messages, and haven't seen this one. So here goes!

I am putting up multiple polls on multiple pages. I can fit 3 polls per page. One of the polls I'd like to have is "What did you think of the information presented on this page?" Rather than create a unique poll for each page with this same question, I was hoping to add the referring page's url to the database. This way I could determine which page was being voted on.
For the results graph, obviously I'd like to just use the data associated with that particular page.

Any way to easily add a field to the database? PHP has the referer() function that can pass the url with the other form data.

Your help is much appreciated!