Must have been one hell of a hole! Consider taking your trucklet to an exhaust shop and have them weld a new connector flange onto your cat. If the flange broke off your exhaust manifold too... same deal. The 2 liter engine exhaust manifold is built like a shorty header out of tubing versus cast metal and should be repairable. Shouldn't be too expensive of a repair = <$100, I'd speculate... unless you go to a Midas type chain shop. They don't call them 'Midas' for no reason. Most of these type shops will also probably try to convince you that your trucklet is in need of new rotors, pads, rear wheel cylinders and a battery. It's amazing, really, how 'well' they look out for their customers.
Seriously, if it broke off... I'd have the shop also carefully inspect the exhaust manifold for rust. The exhaust flanges shouldn't just 'fall off' because you hit a bump. Your front cross member should have absorbed the hit if the hole was that deep before your exhaust would make contact and break your flanges off.
Perryd is right. Both of your O2 sensors are located fore and aft of your first cat converter (on a 2 liter anyway). You don't want to lose the first cat, if you can help it. Your computer will be throwing 'check engine lights' continuously. Although I have heard of these trucks running around with hollowed out cat converters.