If you click a hyperlink within a sharepoint web part you may have noticed that the page loads within the frame of the web part. This is because it is just that, a frame - so you need to go back to old school HTML to get it to use the full parent page (or the frame host)
Simply add the target='_parent' property:-
my new page
the asp.net HyperLink control also has the target property - again this just needs to be set to parent.