It would be a bit easier to answer your question if you could give a little more info about your brew... Such as: your brew size, OG, how much cherries you added, what kind/how much of fresh vanilla was added (extract, beans, ext...), how long have they sat in the secondary, ect...
But if I had to give a suggestion based off your current info, I would say to let it sit in secondary longer (assuming time is not an issue). If this doesn't work after a few months then add more. It's all up to you and your taste buds and that's the great part!