I think either regime should be fine (aside from the fact that I think Mehdi's 5x5 is 5x5 and not 3x5, but hey) for a general workout, but if you want bigger with flab loss, I'd ditch the cardio and spend the extra time on the weights.
Getting bigger means lifting bigger - the 5x5 routine is acknowledged as being a great basis for this, but you'll have to concentrate on your lifts and the weight you're shifting (needs to be close to your maximum).
Cardio for flab loss is great, but 20-30 minutes each session won't work magic in a hurry, subject to your particular workout when on the treadmill/cycle machine.
All of this is pretty irrelevant, however, if you won't let us look at your diet: you can do all the lifting/cardio in the world, but if you're eating either rubbish or the wrong balance/quantities of food, then you won't cut your bodyfat and you won't make the size gains you're after.
Your actions: take a step back, post your diet, take any advice on board, stick to it, then start your workout routine (once we've fixed that, too).