Injured arm

[dcduo]

Hey, a few years back i had broken my left arm pretty badly (both bones, straight across) and had to get plates fashioned in it for around 12 months. Even now, 3 or so years on it is still dramatically weaker than my right, muscle wise. Any exercise i do, be it weight lifting, press-ups or pull ups are made harder, and it seems that my right arm benefits much more from them than my left, oddly.

I am left with one big arm and one lesser and it looks rather stupid. Are there any exercises or techniques i could follow in order to build my injured arm up to sync?

Any help is much appreciated,
Dc.