Wow, that is one part that scares me about Tri's is getting kicked by a breast stroker and losing my googles or worse. It is a serious stroke of bad luck to had a hand broken by that though. I understand that usually weaker swimmers do it and even some veterans I know do it when the water is really cold and the body starts to panic/tighten up involuntarily.

Why don't you just let the hand heal and as other have stated put in more running miles. Or relegate yourself to a stationary bike or spin bike or even stick to the indoor trainer for biking miles. That way you don't have to lean on the bars at all.