What king of brake is it? It's definately possible but probably easier for you to just trade it for a narrower with someone.
I've done the opposite a couple of time (90-ish to 125) and it should be similar. Just put the brake in a vice (clamp it on the inside of the bend, this can be a bit of a struggle to do good), bash it with a hammer until it's so close to straight you can get it, then clamp it in the vice where the old bend were (this should make it totally straight). Clamp it down again, with the edge of the vice where you want the bend to be and hammer it until it has the right shape (make sure you have the brake so it will be bent a little backwards before you start hammer it, just like the original bend). I've done this to three sets of brakes, all of them turned out good enough, two sets turned out perfect as in you could hardly tell they were bent (aside from the marks from the vice).
I have only done this with salomon brakes and know that some other brakes will snap from this treatment so if you try it make sure to search the interwebs about how much of a beating you brakes can take. FKS-brakes are known to snap pretty easy.
Best option is still to trade them, especially if possibly breaking them isn't an option.
