(1) one way to do this is to write some script, such as perl to translate the binary file to text file
(2) Or you can use $fread function
I don't have simulation tool with me right now, so I can not tell for sure if you need to use system verilog (.sv file) when you use the $fread. But do check out the functions provided by system verilog, which has a richer set of functions for file i/o
I don't think you need PLI, that is too complicated for your case. Even if you do need to communicate between C and Verilog, try to use system verilog's DPI, which is much easier to use than PLI.