I've owned a 2004 automatic Lexus IS300 for.

I've owned a 2004 automatic Lexus IS300 for about 2 years now and not too long ago I ended up getting into an accident where my radiator and fan got pushed up resulting in my hood sticking out a bit. I finally got around to taking my car apart and lowering the inside base to get the radiator and fan lower to get my hood back in place which was a success. I then put everything back into place but I completely forgot I drained out the radiator before doing so and I forgot to completely fill in the radiator with fluid/water. I then decided to drive out of town for about an hour. I was 30mins into my destination and next thing you know I came to a sudden brake, I was driving about 65-80 for a good half hour. Once I slightly tapped on the brake next thing you know my car started to steam like crazy from the hood and I pulled off onto the side of the freeway immediately. It was steaming so much it looked like cheech and chong's was smoking in my hood @.@ As I tried to pull over on the side of the road I could feel my wheel stiffening up. As soon as I pulled over I opened up my hood to let it air out all the steam. (The steam was white) I waited a bit for a tow truck to come pick up my car and let the car cool down to check the results. There was white residue of some type all over the insides and I noticed that the hose connected to the radiator that was lightweight slipping off the radiator. I tried to tighten it and it didnt work so next thing I did was unhook the hose. What I discovered when I unhooked the hose the piping from the radiator was cracking and chipping off and the pipe seemed to be flaking. I was wondering if anyone knows the results of driving on low radiator fluid and what I may have to do to fix this up. I probably missed out on some key facts but everything I could think of was off the top of my head. Can someone help me and tell me what I could possibly do to fix this? Sorry for this being all over the place I'm really worried about my car One last thing I forgot to mention while I was pulling over the steam was coming out of the hood, I couldnt tell if there was steam coming out of my exhaust or if it was because so much steam was coming from the hood. I was wondering If you could also give me an estimate on a blown head gasket if that is the situation here thank you~