Trim Issue

Hi

I am trying to use the trim plugin to trim a google alert rss feed url and to trim off the front 33 characters and 109 character from the right to get the url in the middle to be just the base url. I have set up the plugin correctly and it is not doing what its supposed ? Plus I wanted to add the plugin entity decode and that also doesn't seem to be working ?

Does this module work with rss feeds?

http://www.google.com/url?sa=X&q=
-----url needed
http%3A//www.rollingstone.com/music/news/chili-peppers-neil-young-jack-white-blac...
-----url needed
&ct=ga&cad=CAcQARgBIAAoATAAOABA7tHs_QRIAlAAWABiBWVuLVVT&cd=Ssi-dxG-suk&usg=AFQjCNGGqfR87j6MisLOPHiK01tmERP19w

Any pointers? I can add any info that would be helpful thanks !

Nick