Hello Benny,
Avoid bicep work and get stuck into some explosive tricep and shoulder work which closely simulates the action of a punch. The exercises I can think of right now that may come in handy would be EZ bar tricep bench press. Ez bar because it'll be easier on your wrists. Aim for explosive reps off the chest in the range of 12-20.
Another exercise which I've never done but would seem appropriate in your case is to actually grab two light dumbells that will allow you to accomplish 30 reps, and perform shadow punching with them.
Military press is a compound exercise that will generate plenty of power in the tricep and shoulder areas used for punching as well.
Also, don’t underestimate your own bodyweight by incorporating some pushups into the mix.
PS: I hope you're doing some leg work as in squats. After all, that's where the force of your pucnch is driven from.
Fadi.