That code isn't actually PHP code, but forum code. PHP code is much, much more technical and scary. But, to get your image to link to your collection do this:
[url=http://www.rfgeneration.com/cgi-bin/collection.pl?action=profile&name=Arqueologia%20Digital&folder=Collection]IMG[/url]
where IMG is the image code that you currently have in your signature.
You could also this tag to get your website image to link to your actual website.