SQL & PL/SQL

I am a SQL Server developer who is trying to to learn Oracle SQL. I am trying to write a query that will 1) determine the month number and if the number is 10, 11, or 12, will return '01-Oct-' of the current Calendar year. If the month number is between 1 and 9, it returns '01- Oct-' of the last Calendar year (YYYY = current Calendar year minus 1 year).

I was playing with the EXTRACT function to get the year and month, but was unable to formulate the '1-Oct-YYYY' where YYYY is the current or previous calendar year, depending on whether the SYSDATE falls before or after 1-October.

Could anyone point me to an example of how to do this in Oracle?