Your example looks strange (HTML with a misplaced <?xml ..> declaration). If the whole document is well-formed (it seems to be), then XSLT may help you. Unfortunately, we currently don't have an XSLT plugin, and it's not in our immediate list of priorities.
You can still use XSLT using "Run External Command" (you'll need some sort of command-line XSLT shell - there probably are many). To use XSLT, you'll need to save your HTML to the file system using "Write Resource" (if your XSLT shell can't read the URL directly), and obtain the result either using <Output> exit of "Run External Command" or using "Read Resource".
For best results, use the Firefox browser..