Er... you need accommodation from Oct. 1? Start looking in May.
On July 1 there were a grand total of
125 apartments free - in Zürich, a city of 375,000. The housing market is extremely tight here; most apartments change hands through personal connections and don't even make it onto the market, or are on it for only a matter of hours.
Hopefully your new employer can fix you up with something temporary. Ask them. Otherwise, my advice is to put your commuter hat on and start looking at suburbs like Thalwil, Winterthur and Basel.