You will need to get more serious about your diet if you want to get bigger and more muscular. Simply guessing how much you eat day in and day out will not cut it. When you start feeding your body the right amount of protein, carbs, fats, and calories you will make faster gains in the gym. Bodybuilding champions are made in the kitchen.
A good book to help you learn how much protein, carbs, fat, and calories are in the food you eat is "The Complete Book of Food Counts" you can get this at Amazon.com This book is 800+ pages and has nutrition info for practically every single food you can think of.
You also need to get a food scale so you can weigh and measure how much you are eating. Simply guessing or eating until you are full is not good enough. You need to measure exactly how much you are eating and write it down. This will make gaining muscle a lot easier. Most guys fail to make gains in size and strength simply because they don't keep track of their nutrition. I know because I was like this myself when I started. It was only when I started keeping track of my food intake that I was able to make some solid gains in size and strength.
To gain muscular size you should eat:
250 grams of protein per day
450 grams of carbohydrates per day
100 grams of fat per day
(This will equal approx. 3700 calories per day)
Eat 5-6 times per day so each meal should contain 50 grams of protein, 90 grams of carbs, and 20 grams of fat. Some of your meals will be bigger then others, but these are good numbers to aim for with each meal.
Protein powders such as Optimum Nutrition Whey protein at: http://totfit.safeshopper.com/81/986.htm will make it easier and a lot cheaper to get extra protein in your diet.
Your workout routine look good. But here are a few suggestions:
Try using dumbbells for your bench presses instead of a barbell. You can alternate back and forth by using dumbbell bench presses for a couple weeks and then using barbell bench presses for a couple weeks. Dumbbell bench presses will really work the smaller stabilizer muscles in your chest, shoulders, and triceps.
With your back workouts you should include chin ups and dead lifts. Chin ups will help build up your back and arms. Dead lifts will really help thicken your back and make you bigger and stronger all over.
With your arm workouts do less exercises, but really focus on make strength gains in the basic movements.
Here is a good arm routine you can try:
Barbell curls: 2 warm up sets, 2 heavy sets of 6 reps
Tricep push downs: 2 warm up sets, 2 heavy sets of 6 reps
Dumbbell curls: 3 sets of 10 reps
Over head dumbbell extensions: 3 sets of 10 reps
Each arm workout if you can complete the heavy sets of 6 reps with good form, up the weight by 5 lbs. for your next workout. You can use this same idea with your other body parts as well. Instead of trying to do a lot of exercises. Focus on making steady strength gains in the basic exercises. A bigger muscle is a stronger muscle, getting strong is the key to getting big.