If you are looking to put on size up top, then work your legs also. It increases your GH production. There are many, many reasons to work legs....even if you don't care about the lower half of your body.

Protein bars can be good. You should be getting most of your protein from whole foods though. Compound lifts and eating are what will be putting on size for you. Squats, dead lifts, bench press, etc. Look at some of the routines in the training forum. Pick one and stick with it. Read the "How to Bulk" thread in the nutrition forum. I don't know if there are any twice a week workouts. You should be doing total body workouts if you're only going to lift twice a week.

Someone else could probably give some advice about what routine might work well...although I think you'll have to make something up if you're only lifting twice a week.

Here is an idea:

Mon:
Squats 4X8
Bench Press 4X8
Rows 4X8
Bicep/tricep (low volume)

Thur:
Deadlifts 4X8
Military Press 4X8
Pull ups 4X8
Bicep/tricep (low volume)