I've never designed such type of interface but I can try to give you some idea.
About voltage you can set-up a trasformer with reduction primary to secondary ratio then make the measurement by using a cheaper microcontroller and send the data stream trough a dedicated serial optoisolated interface to the your system, regarding the current you can use a Hall sensor and then send the data stream in a similar way. In order to choiche the device you need also to know the resolution of your system (e.g. current is into the mA or several A range?).
As a first approach then I'm thinking to set a main line powered interface able to communicate to the your board by using a optoisolated serial link.
Bye
Powermos