I'm very much on a learning curve with From Light to Dark and Back Again but I have learned not to panic. It is important to do what you can publicity wise as well as you can, even thought it may not be as much as you were hoping for initially. The thing to remember is you, assuming you are planning to write more than one book, will always be getting the word out about your debut (and other works) when going to festivals etc. So take a deep breath, work out where and how you'd like to advertise and then go and see people to make it happen.
Some local through the door magazines will take an advert (though some charge). I had hoped to get a press release out though ran out of time and I was pleased to see my item went into the Books Event horizon, which is due tomorrow.