If the required ports have been blocked, there's not much you can do but ask someone from the IT department if they could/would unblock the required port(s). I wouldn't hold much hope, though, for two reasons:
1.) This is likely for personal business, something frowned upon in the workplace.
2.) If they have tight security, they won't want to open a hole without a good reason.

Also note that we won't help circumvent the security precautions and limitations imposed by your place of employment, so other responses will be slim.