How do I convert time into a string with AppleScript?

I'm trying to write an AppleScript that gives me the time remaining and total time of the currently playing iTunes track. I'd like it to be formatted as minutes:seconds / minutes:seconds. If that is impossible, seconds / seconds would work as well.

Here's what I've got so far:

on run
set info to ""
set info2 to ""
tell application "System Events"
set num to count (every process whose name is "iTunes")
end tell
if num > 0 then
tell application "iTunes"
if player state is playing then
set when to player position
set long to time of current track
time of long as string
set info to when & " / " & long as string
end if
end tell
end if
return info
end run

Now the problem is it can't get long as a string because it is formatted as 3:31 (the total time of the track). If I try to divide long by 60 to get the seconds, it won't work because it can't make 3:31 into a real number. Converting when to a minutes:seconds format would work just as well for me.

Thanks for your help.

Excellent! That worked. After rounding to the nearest integer it's perfect. Thank you.

Is there a way to change the seconds into the minutes:seconds format?

Sorry for the third post in a row, but I've made some progress.

I now have this:

on run
set info to ""
tell application "System Events"
set num to count (every process whose name is "iTunes")
end tell
if num > 0 then
tell application "iTunes"
if player state is playing then
set when to player position
set whenStr to (when div 60) & ":" & (when mod 60) as text
set long to time of current track
set info to whenStr & " / " & long as string
end if
end tell
end if
return info
end run

And it works well, except for one thing. When the number of seconds is less than 10, there is no zero in front of it. It displays 3:5, rather than 3:05. Any ideas?