I guess I’m wondering why you are wanting to make those “nofollow”. By doing so, you are losing out on whatever SEO capital you are earning by sending people from your blog to your social sharing sites. Am I missing something?
If, on the other hand, you want to use that area to link to other sites, you could probably forgo the top bar entirely and use a Graphene action hook widget area, which would give you a great deal more control over your links.