I'm not sure about Air Lib (although I know there was a lot of turmoil there as they were one of the more loss-making investments that Swissair made and they had some labor problems) but 3-4 hours should be no problem from CDG - ORY. There's an Air France bus service and the RER.

The RER (which is 16.16 Euro) is a nice way to go but I think the bus (11.43 Euro) may be better - faster, cheaper, likely easier to get luggage in to and out of. It leaves every 20 minutes in the morning and every 30 minutes in the afternoon from halls b,c and f at CDG2 and the arrivals level at CDG1.