This can read all single values of your Installer.ini without any use of plugin. Check example
here or
here
Code:
#define ReadInstaller(Section, Key, Default) ReadIni(SourcePath + "Game\Installer.ini", Section, Key, Default)
[Setup]
AllowNoIcons=yes
AllowRootDirectory=true
AppId={{F9787790-D97B-457E-80DA-F69C91F862A8}
AppName={#ReadInstaller("Installer", "Name", "")}
AppVersion=1.0
AppCopyright=Random_Gamertags
DefaultDirName=C:\{#ReadInstaller("Installer", "DirName", "")}