If you want to convert from the CD layer, many software can do, even windows media player that come with windows will do.
If you want to convert the SACD layer, there is no easy way to do it with computer, as most of the DVD rom players do not support SACD fomat. The easilest way to convert SACD to other format, you will need a old version of PS3 that come with support of SACD, and you need to flash custom firmware to convert the SACD to SACD iso. Then you can use that iso to dsf or dff. I am not sure foobar support DSF or not. FOr sure foobar support dff file. then you can use foovar to convert to mp3. You need plugin for foovar to play dff though.
But if you seeking for SACD sound is it a waste to convert to mp3?? At least convert to wav then. just a suggestion.