Now. This is hyper specific. Specially considering as I have made an account just for this. 

I only have the DAT file and I lack the SAV file. 

Is there a way for me to create a SAV file using the data on the DAT file. (if possible)
Or to transfer/convert the DAT file into the SAV file (if possible)

What's the difference between both too?. 

Thanks in advance

DAT file only stores data to display in saveload menu without reading the saves' insides, so no.