Overheated, compression loss, worried sick

I scheduled a new radiator replacement this Wednesday. I had been driving the car to work, about a 30 mile trip, and keeping a close eye on the temp guage. Last Friday, the temp went up and stopped right at 120, but after about 15 minutes the engine started to loose power. I pulled over and the engine got really hot and blew a radiator hose when I shut it off. Now, it has uneven compression, lots of air and bubbles pumping into the radiator reserve tank, and some small ***** of oil floating around in the reserve tank as well.
My mechanic tells me (hasn't actually seen the car yet) that overheating usually blows the head gasket. I just had the head rebuilt about a year ago, and I'm worried that, being aluminum, the heat may have cracked it. Does anyone have any experience with severe overheating with this engine? Does the head gasket usually blow, or does the head usually crack? I really like the car, but I'm just worried about investing (yet again) more than the blue book value on this car to get it fixed.
Thank you for any advice.



