First you may want to accept the truth that you do want to date her and that is perfectly okay. Secondly, before you go to sleep, ask the Universe to be with her.
The whole concept of "letting go" is quite difficult to do. I think it is for everyone b/c we are emotional beings. To let go, just means start focusing on doing things for yourself to make you happy. The happier you are single the more happiness will be brought to you.
Hope that helps!!