One thing all my clients will say is Im tough on their diets! As I know (and so do they I think :p) that this is the key to any weight loss / muscle building goal! However getting ideas for snacks are tough as I am not the most creative person. However I have been reading over some sites and here are some ideas to get you through the afternoon!
http://liftforlife.com/content/bodybuilding-fitness-diet-health-articles/diet-articles/727-protein-bar (some awesome ideas for your protein powder)
Hope this was helpful and I will see you in the gym very soon!