Tools used in this guide.
First you will need a method of getting your PS1 save files transfered over to your PC a giude for doing this can be found here
Once you have your raw PS1 save files transfered over to your PC you can convert them into .mcs files by simply dragging and dropping them into PSXRC.
N.B. some files may not be recognised by windows due to how they are named so you must rename them first in ulaunch (they can later be renamed back to their original name.)
Now use PSXGE to open the .mcs files and save them as a memory card image with the extension .mc
Rename the .mc file to .mcr this will allow the saves to be opened in an emulator such as ePSXe