It depends HOW you want to install your driver(s).
Are they .exe files and you want to execute it one after another silently or do you want to do a "real" install of the driver files with your script?
if they are .exe files you only have to find the silent switches (for example: setup.exe /S).
What switch you have to use depends on the install engine the driver have. Installshield has another one as InnoSetup. Just google for "install silent switches".
if you found some you have to test it and if they work you can implement it in you code:
setoutpath $PLUGINSDIR ;set %temp% as otput dir
File "PrinterDrvSetup.exe" ;extract this exe to %temp%
ExecWait '"$PLUGINSDIR\PrinterDrvSetup.exe" /S' ;execute Setup from %temp% silently and wait for finish
But if you want to create a "real" driver installer it will be more complicated. Have a look to the InstDrv Plugin.