I'd really just suggest working on your weak arm harder than your right arm..

You may feel like your doing your right arm an injustice by not working it to it's peak capacity, but you'll feel much better when both arms are back to the strength they were & then you can go all out with both arms..

Do a lot of dumbel work & say you can do 15 reps before your right arm gets sore, stop your right arm at say, 10, and continue to lift with your left arm to about 12 or 13 & so on...

The right arm will get a slight rest during this period (do it for 2 or 3 months) & you should notice your left arm catching up... Always finish your right arm reps before they get really sore, but continue on with your left arm to the point of failure.

I had the problem of one arm being a lot weaker than the other, and while your working on evening them up, you really do feel like the strength of your good arm is going to waste & it's tempting to go back and work that arm as hard as you can as well,,, but just stick it out.. it's only 2 - 3 months out of your entire life that your not working your right arm hard, so it's not the end of the world... Just stick at it, and you'll get the results you want.