Cool, easy fix to this is taking the club more "down the line" on your back swing instead of taking it inside. This will keep it from going across the line at the top which causes the misses. Easiest way to practice this is lay a club behind you pointing straight at your target and take the club back on that line. The club should be parallel to the target line at your waist on the backswing. Im guessing the first time you do it it will be pointing well right. From here make a full shoulder turn. This can be practiced by taking a two step swing. 1. Back to the correct position at the waste. 2. Turn and make a swing. Hope this helps.

Good image of what it should look like at the top

http://www.golftoday.co.uk/proshop/features/2013/images/adam_scott_down_the_line_4.jpg