I would advise using the other data point details page for these exports if possible. If not, a little script can convert the timestamps. Using python:

from datetime import datetime, date
import re

inFile = open("/path/to/your/export")
outFile = open("/path/to/your/output.csv", "w+")

def myFormatter(dt) :
  if isinstance(dt, datetime) or isinstance(dt, date) :
     return dt.strftime("%m/%d/%y %I:%M:%S %p")
  else :
    print "Bad date!"
    return "Converting error"

for line in inFile:
  g = line.replace("\"","").split(",")
  if len(g) < 2 or re.search("[0-9]+", g[1]) is None :
    continue
  #add back the quotes if you want
  outFile.write(g[0] + "," + myFormatter(datetime.fromtimestamp( int(g[1])/1000 )) + "," + g[2])

inFile.close()
outFile.close()