Question about '00 Outback AC & head-gasket problems?

I'm on a limited budget and need to buy a car. I'd really like a Subaru, but most are out of my price range. I found an '00 Outback in my price range, but the ad says that the AC needs to be recharged and the head-gasket externally leaks coolant, but has never overheated and is drivable. How much will it cost to fix the AC + head-gasket? Will the car have further problems after making the fixes or should it be good to go? How are Subaru's transmissions?