The most common cause for a lack of power is that players fail to fully coil.
Are your swinging your shoulders as far back from the ball as Andy in your backswing?
Are you driving with your legs as powerfully as Andy?
Consistency, on the other hand, often fails from perfect body positioning - not getting in the optimal position for a great contact point.
Are you coming out of a split step every time your opponent hits the ball?
Are you making the small adjustment steps as the ball gets closer, so that you neither "crowd yourself" or are too far from the ball?
Do you keep your eye on the ball until contact?
How To Look At The Ball Like Roger Federer http://www.revolutionarytennis.com/f...technique.html
You may just need more practice to redevelop the "muscle memory" so that positioning, coiling/uncoiling and timing become second nature like before you took time away from the court.
If there is time for you to practice, but no one is available, don't overlook hitting against the wall.
You can get a lot of hits in over a relatively brief time at the wall, redeveloping your old skills.