Regular expressions to create a data frame (XML)

<?xml version="1.0"?>
  <!DOCTYPE temperatures SYSTEM "pointnemotemp.dtd">
  <temperatures>
  <variable>Mean TS from clear sky composite (kelvin)</variable>
  <filename>ISCCPMonthly_avg.nc</filename>
  <filepath>/usr/local/fer_dsets/data/</filepath>
  <subset>93 points (TIME)</subset>
  <longitude>123.8W(-123.8)</longitude>
  <latitude>48.8S</latitude>
  <case date="16-JAN-1994" temperature="278.9"/>
  <case date="16-FEB-1994" temperature="280"/>
  <case date="16-MAR-1994" temperature="278.9"/>
  <case date="16-APR-1994" temperature="278.9"/>
  </temperatures>

1) How can I read the xml in R using xmltreeparse or xml parse.

2)Using the regular expressions how can I create a data frame using date and temperature as variables. could you provide the whole syntax for both the questions if not a problem.