Don't get a co-founder just for the sake of your YC application. In fact, it might hurt you chances of getting accepted if you don't have the right person. From

Don't get a co-founder just for the sake of your YC application. In fact, it might hurt you chances of getting accepted if you don't have the right person. From what I have seen in the YC application you need sell not only your idea but also your team. There have been cases where single person team have been accepted, e.g., Dropbox. You should keep looking for a co-founder irrespective of all this. You should be able to sell your idea to someone smart and intelligent until then you really don't know how good the idea is.