If you want a pre-mixed post-workout drink then get some Fast Gain XXLs by USA Strength Systems.
If you can bear with mixing it at home then grab some Surge by Biotest...excellent stuff!
Then you can always mix some Cyto Max with some protein powder.
Or if you feel like playing around in the kitchen, get some BCAAs, whey hydrosylate, maltodextrin, and glucose...mix it up and perfecto.