Do chromatic scale exercises using one finger per fret, on the higher ( 5th and above) frets to avoid over reaching.
Another exercise is to place the four fingers on say, frets 5,6,7, and 8. Keeping your index, middle and ring fingers down on the frets, 5, 6, and 7, try lifting the pinkie.
Yet another is this :
http://www.youtube.com/watch?v=3iGRkzUehA0
It will take a while to build up strength in the pinkie. These exercises worked for me. Stick with them and they should do for you also.
BTW, I agree about the finger exercise gadgets.