Book through Negril One Stop, it won't cost you any more than if you did it yourself and they are very helpful.
As for the beach resorts...You can't go wrong with either Charela or Country Country. I might pick Charela for the location but they are both nice. Of the two cliff resorts, it depends what you are looking for. Tensing is a beautiful property and very quiet. Catcha is also a beautiful property, smaller, and a better bar scene...I have stayed at both and would choose Catcha again mostly because of the awesome staff.