It might take away some of the confusion if you realize that the first "and" should really be "to"--you are sending an email which is going to say something. You are not sending an email and saying. Also, you could use a semi-colon to separate this into clearer segments, but it would be better to just make it two sentences: Is it better to send an email today or tomorrow to say that I'm leaving the country, and then come to Singapore?
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