Blown Head gasket

So I'm just looking for some information and any help on why and what I should do about my head gasket
going. I just got my cobalt not even two years ago.. and already the head gasket is busted. :( Background: I
bought it w/ 12,000 miles and it was basically brand new. I've maintained it properly, with the exception of a
mistake on my part to let my ex bf change the oil. He insisted that I shouldn't (even though I've done it plenty
before, either because he's an idiot or didn't think I could - I don't know). Anyway, after taking it to his mom's
for no reason and hitting a serious sheet of metal on the highway and busting my side panel (sorry for ranting)
he supposedly changed the oil. Granted it was black a week later when I checked it so I did it again. That was
last august. It had been running fine since, but within the last two months running a bit hot (~210F) The coolant
and everything looked fine. 2 weeks ago the temp shot up to 300+ (to the point where it just said ---F on the
info system). After stopping multiple times to let it cool down I made it home (I was about an hour out) and it
died that night smoking and shaking. Checked it the next day - oil was 2x as full and tinted orange with no
coolant left in the reservoir. I only have 40K miles on this car and I'm not looking to get rid of it (besides, I still
owe a decent chunk of change on it). I called around and the dealership I got it from (Dorchel used in
Henrietta) said it would be about $840 in labor and no est. on parts. Also, someone my family knows owns the
garage Eagle Transmission in Rochester. I don't know anything about the work they do there but he said him
and his buddy would do it for $1500. I'm used to my beater cars and, between my dad and I, fixing them
ourselves. This is out of my knowledge base :( PLEASE HELP!!! (Sorry such a long post.)