You can export your words ("Export" button at the top of any word list) and make Anki cards out of them manually, but no, you can't transfer Renshuu mastery directly into Anki.
If there is anything else you need in the export button so make it easier to do this, do let me know - I'd be happy to add extra fields to make the export process easier.
Also, you may want to use the Tools > Advanced Search, since it allows for export, and makes it easier to grab, for example, everything you've studied in renshuu.
