I would not make it too complicated. In general, you want to find out which 
client has clones which will expire in more than a months.
So i would use a command like:

  mminfo -q "pool=clone_pool,clretent>=03/03/2012" -r 
"client,name,savetime,clretent" -xc, > outfile

and import and filter the result in Excel.

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