If I understand correctly what you want, then you just need to put your part of the script first then mine:
e.g.
[codex]
tell application "iTunes"
play playlist "music"
end tell
tell application "System Events"
-- Command Esc. to start Front Row
key code 53 using command down
-- wait for Front Row to be ready for keyboard input
delay 4
-- Press Return twice (Music -> currently playing)
key code 36
key code 36
end tell
[/codex]