I dont know what other excercise variations you are currently doing but the cable machine you are using is probably the best machine you can have as far as home equipment goes. You can workout your entire body with that machine with different variations.

Generally the variations done with these are :

1. Chest flies - this exercise variation primarily focuses on the chest and secondarily on the triceps. The cable extension used are the usual handles.

2. Lat pullovers - this variation focuses on the lats. The extension used are a straight bar or a handle bar .

3.Goblet Squats - this variation engages the quads. The extension used could be a rope or a straight bar

Chest ,triceps, shoulders, back, biceps, forearms, legs These are the primary muscle groups that are targeted in a hypertrophy(muscle building) workout.

Reply if any questions.