Oil filter/coolant housing leak?

I took my vehicle to Midas for an oil change. They call me to pick it up. When I got there I paid for the oil change then they told me the car has to stay overnight because there's a major oil leak from my oil coolant housing and they need to replace it and 2 hoses before I can drive it. Cost at $3,000.00.

I'm going today to look at it and see if I'm able to drive it home or will I have to tow it. I told Midas I'd have it fixed by someone else. My question is, how do I know I'm buying the right parts? So, I can gauge costs and is this common? Will I be able to drive it if the leak isn't too bad? Please help!