These type of routines are based solely around the big compounds for a reason and adding additional exercises will likely impact on your overall gains. Just keep upping the weight slowly each week, concentrate on your form and it will get tough sooner rather than later.
It's an excellent variant of the row although it requires very strict form to maximise gains.
http://stronglifts.com/how-to-perform-the-pendlay-row-with-correct-technique/
As above, follow the routine exercises for exercise, set for set, rep for rep and don't change a thing until you develop a better understanding of each lift, the techniques involved and what your body's capable of.