Joy, you want to block the er and her2, her3 pathway simultaneously. I think that is possible to some degree with diet as turmeric and black tea block the er pathway; green tea, black tea, omega threes fatty acids, ALA and GLA block the her2 pathway; and finally black tea also blocks one of her2's major heterdimerizing partners, her3.
http://her2support.org/vbulletin/showthread.php?t=28953
Most people don't know if they are her1+, unless they've gone out of their way to be tested.However, to those who are her1+, a natural inhibitor MAY be genistein and other isoflavons:
http://www.freepatentsonline.com/6638543.html