1. Thick bar holds for time...
set a thick bar in the power rack just below deadlift lockout height. If you cant get a thick bar build up a regular bar with towels until it is 2 - 3 inches in diameter. This is slightly thicker than the sleeves on a regular olympic bar. Grab the bar and lockout your deadlift with a pronated (overhand) grip. Hold the bar away from the thighs so it can not rest on them. Just hold it till it drops out of your hands on to the pins. Thats one hold. Time it. When you can do 3 holds of 30 secs with a certain weight, increase by 10 kilos.
2. 2 handed pinch.
Get an olympic dumbell, the kind you slide plates on to to build it up to size. Stick one 20kg plate on each side to begin with. Now, place the bell on the edge of a bench and pinch one of the plate edges between the thumb and forefinger of each hand. Step back so you are supporting the weight of the bell and again hold it till it drops. Do 2 sets of these.
3. Wrist roller.
this is a thin bar with a hole in it and a rope through the hole. You put weights on the other end of the rope and then turn the bar in your hands to wrap the rope around the bar, hence raising the weight. If there isnt one in your gym, make one with a broomstick, it is easy. Start at about ten kilos and do 2 sets for each direction of rotating the bar, for a total of 4 sets. Work up by about 2.5 kg a week, and when you can do 55kg in 11 seconds, call me cause then you are stronger than me and i will want to be jealous.

4.Extensions...
These are to balance out your new gripping strength with stronger extensors...this tends to prevent any pains around the elbow or hand that sometimes develop when gripping hard. Get a hairband or thick elastic band and wrap it over your thumb. The other end goes over the tip of one finger, and then all you do is open your hand as wide as you can, like a gripper but in reverse. Do one set for each finger, and add more bands to the set up when you get 15 reps with a given resistance.