Car problems

I bought a 2007 Prius Touring anout a month ago
or so. It has 66,000 miles. It has a salvage title, it
got hit from the back at 59k miles. A dealership
bought it a fixed it and sold it to me after putting
5000 miles on it. It ran perfectly except for light
saying low air in tires after putting in air. I took it on
its first trip, 700 miles from home and while here
the transmission started slipping and then the fan
started blowing constantly annoyingly loud. I had
never heard it .before! I had loaded the back seat
up and dont think vent was blocked but am not
positive! Didn't  stop when stuff was removed! It
also rained alot and it was leaking in the back
hatch door. Water was around the spare tire. Then
the red triangle, yellow brake system light, vcs,
engine lightcame on. My husband changed oil and
transmission fluid. Transmission stopped slipping!
Is driving fine except for fan still blowing! Warning
lights still there. Auto zone diagnosed said hybrid
battery bad! Went to advanced auto parts they
gave me the codes and meanings. C1259hv
system regenerative malfunction current, c1310,  
c1378, p0a80 replace hybrid battery pack,
P3018,battery 8 becomes weak. Since the fan was
running hard we cleaned fan and filters. Didn't help!
checked cooling pump for turbulance and heard it
was running, just to rule that out. My husband took
out hybrid battery and tested each cell they all
showed 7.8 and 7.9. He cleaned the corrosion off
the connections and put it back together.left 12 v.
battery  off 30 min. or more to erase codes.
Started car and all the same lights plus ....abs,  
slippery tires and tires need air blinking! Car won't  
get ready now! Wont drive no more! I haven't  had
any trouble with the 12 volt battery being weak. My
husband checked it and it said 12. something.
Help!