how to update if search patten is found

$cat sample.txt <name>server1</name> Oracle /usr/bin/java/jdk64 <class-path>/run1/getd/commn/modules/oracle.jdbc_11.1.1/ojdbc6dms.jar:/run1/getd/commn/util/jdk64/lib/tools.jar</class-path> -XX:PermSize=128m -XX:MaxPermSize=384m -Xms512m -Xmx512m -XX:NewRatio=2 ............. ............. .............

  <name>server2</name>
  <java-vendor>Oracle</java-vendor>
  <java-home>/usr/bin/java/jdk64</java-home>
  <class-path>/run1/getd/commn/modules/oracle.jdbc_11.1.1/ojdbc6dms.jar:/run1/getd/commn/util/jdk64/lib/tools.jar</class-path>
  <arguments>-XX:PermSize=128m -XX:MaxPermSize=384m -Xms64m -Xmx256m -XX:NewRatio=2 ............. </arguments>

I have a file for my weblogic server, sample.txt like this, so If I see name as server1, I need to update part of arguments to -Xms1024m -Xmx1024m and If I see name as server2 I need to update part of arguments to -Xms256m -Xmx512m. any help on this would be great.