Don't buy any more of those supplements. Finish the bottle by all means, but after that you should buy milk, eggs and meat instead.
And what's the deal with the light weights, do you lift at home? Do you have heavier weights? Access to a gym? A barbell?
I'd suggest not doing a circuit. Do 3 sets of pullups or chinups to failure, then some heavy db rows, then some curls.
Db shoulder presses are best done seated. Work up to a set of ten instead of six sets of three. Do another set to failure with a little less weight. Do heavy lateral raises, some body english is ok, keep the front raises and if possible, do some behind the back lateral raises on a cable station, those are great.
Is that your final goal? Do you train in any other way or is this all you do?