I doubt you will be able to get digits out of Skype, but otherwise this is trivial: use the same parameters in Dial as you would for a locally initiated call or Goto() the context and extension you would use for a locally initiated call.
For future reference, the purpose of the subject is so that people can find interesting questions and so that they can easily re-locate a question. As such it should summarise the contents of the question, not the capabilities of the poster.