This is the holy grail. You can play God of War 2 on your PC using PCSX2, then continue the exact same save on your phone using AetherSX2.
If the download you found is a full Mcd001.ps2 file (usually 8MB), just replace your existing file. save data god of war 2 aether sx2
If you want to skip the grind, you can import a finished save file (often in .max or .psu formats) from sites like GameFAQs . This is the holy grail