how can i load a touchstone format file *.s1p into my workspace with Octave?
It appears that Matlab's RF Toolbox has functions to directly read in Touchstone files. I don't think any of the Octave packages have a compatible capability implemented. s1p/s2p/sNp files are just text files , so you could read in and parse the files manually like any other data file. Alternatively, a web search shows that a few other people seem to have made functions or external packages that might be helpful  to get you started.