Just like Vanilla Ice-cream is the simplest, most boring flavour, Vanilla Radio is the kind of boring radio station where there's nothing exciting played, just the same safe, generally insipid, stuff over and over again.
The song is a call out to all those who are happy to listen to the same stuff to turn it down and find something more exciting. Unfortunately, due to exactly the problem Ginger's singing about, it's a call to arms that didn't get heard by many people...
I think the 'Where's my Elvis' bit is Ginger bemoaning the current lack of the kind of artist who can change everything and excite people the way Elvis did: Elvis was
their Elvis, Where's
MY Elvis? (somewhat ironic considering that to some of us, that's exactly what
He is.

)