Hi,
You cannot leave your computer for more than 15 minutes when flying on IVAO.
You can start the flight on IVAO, then disconnect when you go to sleep, and then re-connect when you are going to land.
But that doesn't count as an IVAO flight (you can submit it on IVAO). Just as an EHM Flight.
About getting information, you need to use a program called FSUIPC and build a library to read the values from it.
If you are using PHP (web based applications) then you need to create an ActiveX component to inject values via a HTTP socket on your site (one of many ways to do it).
Regards,