As other posters have noted, Gagarin is hugely celebrated in Russia. In the US, however, a combination of American provincialism and antipathy towards the Soviet Union (remember that all this happened during the Cold War), led to a lot more attention being paid to Armstrong. read more
According to one piece I read there was a possibility of him coming to New York in March 1962 (to the UN). It appears in the end only Titov came, Gagarin instead visiting Austria and Japan. read more