You should try the 'see-food' diet. That is, if you see food - eat it. Nutrition is a huge part of gaining muscle.
But not just any food. Skip anything with high amounts of refined sugar and fats. You need whole grains, high quality protein and lots of leafy green vegetables. Aim for 3000-3500 calories per day, if you are working out 4-6 times per week.
Breakfast can be 2 eggs scrambled with some added egg whites, a big bowl of oatmeal, and a few pieces of fruit. Snack later on a bagel with all-natural peanut butter. For lunch, have a chicken breast or 2, with a cup of brown rice, and a serving of any vegetable you like. Have a midafternoon snack of maybe some trail mix and an apple. For dinner, an 8oz strip, round, or flank steak, steamed broccoli, and a baked yam/sweet potato/regular potato. Have some cottage cheese (if you can stand it) or yogurt and leftover meat or lunchmeat for a bedtime snack. Substitute different foods for variety. Have a salmon fillet for dinner one night... chicken fajitas the next... whole wheat pasta instead of yams one night... etc. Try not to get bored with your food.
The key thing is to eat every 3 hours if you want to gain weight (or to lose weight for that matter ... just eat smaller amounts and do alot more cardio)
Drink a LOT of water (4 L per day - 4 large water bottles or 8 small bottles).
For supplements, you said you're taking protein after workouts. Try taking some in the morning as well. Also, within 45 minutes of finishing your workout, have a small meal with a high amount of carbohydrates (some fruit, a bagel, juice...). There's a window of opportunity where your muscles suck up those calories to refuel your energy stores, thus leaving you better healed to handle tomorrow's workout.
Consider adding glutamine to your supplementation, and maybe creatine. (edit - just reread your post and noticed that you don't like creatine. I've never had any problems with it). Both will aid in recovery, and help to increase your strength and as a result, size. After adding those two supplements myself, I beat my max weight record in almost every exercise within a few weeks
I wouldn't rely on and specific 'weight gainer' product - much better to eat right for your goals.
Oh, and make sure you aren't running on a treadmill for an hour per session for your cardio aspect. Look up HIIT (high intensity interval training) and do that instead. I warm up at a 6 mph jog for 3 minutes, then sprint at 11.5mph for 1 minute, then back to 6mph for a minute, repeating back and forth for 15 minutes. Feels awesome and doesn't exhaust my glycogen supply and, most importantly, doesn't break down muscle tissue to provide energy to keep running, which can happen in extended duration runs.