Getting the app upgraded or changed to not need 2008 is the hard part. If the app could run on a later version of Windows, this would be really easy. I'm sure you can appreciate how difficult that might be. For custom apps, it could be a lot of code to update. For vendor apps, that app would also probably need to be upgraded to a newer version because the app is also end of life for some years now. In our case, it's a vendor app. No time and money to fix this situation, so we just keep it running and pray.
How much would someone get for getting this done?