you can't switch your application from fiancee to spouse visa if you have already made an application to the embassy but you can call to withdraw it but its not refundable so waste of money if you wanted to...since your wedding will take place next month you can either put it on to hold (in case you get refusal)just in case, the best thing to do is to wait for the result of your application becoz it can come at any time by now...i dont know what would happen if they have gotten your email saying they just have to switch your fiancee visa application to spouse visa and wait until you got married and wait for the marriage certificate i dont think they have much patient and time for that...or if they have that kind of rules
i think you better stick on your fiancee visa application coz you cant have both ways or you will just confused the embassy...