For a three day a week program seperate it into these muscle groups(kiss and will help you gain.) 1.)arms,chest. 2.)legs 3.) back,shoulders 4.) abs,calves(fill in whenever, near impossible to overtrain).
TRAINING SHOULD NOT TAKE MORE THEN 45-60 minutes if your sitting in the gym for two hours you are NOT working.
Your going to want to load creatine pre and post workout, I would suggest Bodybuilding.com - BSN NO-Xplode - Extreme Nitric Oxide & Creatine Surge! On sale now!
First and foremost you NEED TO EAT ALOT OF food. Here is an example of my daily routine(nobody is ever perfect)
8am: 3 eggs,1 cup oatmeal, 1/2 peace of grapefruit
11am: Either a whey shake+fruit or 2 hb eggs+fruit
2pm(preworkout): 2 peaces of wheat bread+can of tuna + green veggie.
4pm(postworkout): Muscle milk(1/2 water 1/2 milk) + fruit.
Now if I am training in mma that night (6-8:30) I will eat again at 5:30 which is usually a veggie+portion of protein+some complex carb(sweet potatoe etc.)
8:30 protien bar(or shake)
10pm veggie,fish or steak or chicken. > sleep.
I carry a 1 gallon jug of water everywhere with me, I look like a nerd but oh well! 1-1.5 gallons a day.
NOW about supplements, DO NOT go with xyience they are VERY overpriced compared to the same supplements from other companies. Get yourself a good multivitamin, 100 whey, muscle milk+creatine(glutamine if your training twice a day) and your set.
Here are some great supplements dont waste your money on gimick ones(there are alot of them).
Bodybuilding.com - Optimum 100% Whey Protein - With Faster-Acting HYDROWHEY! On sale now!
Bodybuilding.com - Universal Animal Pak - The Ultimate Training Pak! On sale now!
Bodybuilding.com - CytoSport Muscle Milk - Muscle Growth And Repair! On sale now!
Now you need to really tinker with your diet to fit your bodyweight(get body for life from Bill Philips) and last but not least TRIAL AND ERROR+ LOG EVERYTHING YOU EAT so you can understand what is and what is not working for YOUR body. Good luck!
And yes stronger entails gaining muscle=weight=size.