I will advice you don' t do that, for some reason your company block all the incoming info "of those sites". Better stay away doing that kind of stuff.
I wonder, your company let you bring a laptop if so, so go for it and connect your phone to your laptop. But if they blocked all the sites, is for protected all the info, from virus, stolen info, so this happen to you, they can track you very easy you were the problem using the company pc on the internet.
Better use your cell phone to navigate, if the company let you doing that.