Hi.
"e.g. Queen Winfrey earns euros on river in musical venue" = 'Royal Opera House'. River Ouse or anagram involving euros? Winfrey??
"Eat here after seizing base captured by US spies" = 'cafeteria'. Anagram of After/CIA but with an e left over. Base=e???
"Affairs are important to head of state" = 'matters'. Is this just a case of Important=Matter then add S(tate)? Seems a poor clue...
Many thanks