By the sound of things you have to qualify in order to be able to renew your CCW permit.
(Please note... I am not a doctor or a therapist. However I have read of people with similar issues and have seen these exercises suggested.)
If you want to keep using the same firearm that you already have and not change to something lighter with an easier slide to rack, or change to a revolver... consider getting a "hand exerciser" from you local sporting goods store (or possibly Walmart). Start by doing approximately 10-20 squeezes on the hand exerciser, a couple of times a day, in order to build up the grasping strength of your hand muscles. You can do this while you watch television. You can always increase the repetitions as the exercising gets easier... or decrease them if they seem to be too much. The main thing is to keep exercising your hand muscles to strengthen your grip.
In regard to strengthening your arm muscles to be able to hold & point your firearm... try holding a standard sized can of vegetables (in your shooting hand) with your arm extended parallel to the floor. Do each repetition for approximately 30 seconds. Do about 10-20 repetitions a day. Increase the repetitions and/or length of time as you find holding the can extended gets easier.
You can alternate doing the exercises, doing the hand exercise one day and the arm exercise the next... or just do both on the same day.
Combined, these exercises should help to strengthen your grip and arm strength. They should help make it easier for you to grasp and rack the slide, as well as maintain the strength to keep your arm comfortably extended arm while holding/aiming your firearm.
The only exercise left will be for you to go to the range and touch off a few rounds.
Good luck!